Q: I'd like to include some oak trees in my garden but am not sure how to treat them in terms of watering and pruning.
A: Great idea! Oaks are a keystone species and support a huge number of our native wildlife, especially our insects. They support at least 40 butterflies and moths, and dozens of gall wasps, for example. The leaf litter, and the arthropods it shelters, provides food and habitat for lizards, birds, and so on, as well as decomposing to feed the tree and surrounding plants. Most nursery oaks have been grown with frequent watering (and often fertilizing too) so the transition to a garden with moderate watering should be no problem. Any volunteers that have appeared are also adapted to whatever the conditions are where they rooted. Oaks are fairly fast growers, and may need some pruning to produce the shape you want, or to get rid of dead wood. Unlike many other trees, tho, oaks are best pruned in the summer when they are semi-dormant. Pruning in the winter can make them more susceptible to fungal diseases.
Q: I'd like to grow some classic garden bulbs. Any suggestions about what to buy and how to plant them?
A: First, in general, spring bloomers need to be planted in the fall, and summer bloomers in the spring, so you need to buy them well in advance of the time you want them to bloom. That said, I've planted daffodils in pots in lale winter and they have still bloomed. In our mild winter climate, many of the classic bulbs such as tulips and hyacinths won't bloom unless they are chilled in the refrigerator for some weeks (you can google detailed info), and others will do fine in the ground for a few years and then peter out. Many bulbs do well in pots and you can layer them: for instance plant hyachinths with the bottom of the bulb about 6" down, daffs and crocuses with the bottom of the bulb about 4" down, ranunculus, grape hyacinths and freesias with the bottoms about 2" down . You can let the foliage die down naturally and plant the bulbs in the garden but they may not flower again for a few years, even if you fed them well. Some iris, such as our native Pacific Coast ones, do fine as permanent additions to the landscape, as do some exotics such as sparaxis. A note: paper white narcissus have come back and bloomed for me in my parking strip for years with very little attention.
Q: How can I keep my vegetables growing and still do my best to meet the current water restrictions?
Q: How can I keep my vegetables growing and still do my best to meet the current water restrictions?
A: Laying soaker hoses (the kind that ooze throughout their entire length) 1-2 ft apart throughout the bed (the closer spacing for fast-draining soils where the water moves down faster than outward) is a great way to do this. Covering the hose with mulch will help reduce evaporation, and using a quick connecter will make it easy to move your regular garden hose from one soaker hose to another. Another method is to bury leftover 5 gal plastic pots about half their depth near plants to be watered. When you fill the pot, the water will leak out the holes in the bottom, targeting the roots. Even 1 gal plastic pots will work, although they won't do as well for deep-rooted plants like tomatoes as the 5 gal ones will, and may need to be refilled several times to make sure that the water is reaching the whole of the rooting area. Once the soil is wet to the desired depth, then stick your finger in the soil every day (or use a moisture meter) to see if the top two or three inches are still damp, If so, you can delay watering a few days or more depending on how hot it is. For either method, watering early or late is best as that reduces evaporative loss.
Q: Squirrels keep digging holes in the soil in my potted plants. Is there an easy way to discourage this?
A: A tried and true method is to cut a piece of hardware cloth to fit the top of the pot, make a slit in it with a hole at the center and put this on top of the soil and around the base of the plant. The netting from bags of onions also works, especially the purple net from purple onions--this just fades into the background. Just cut it so it can lie more or less flat over the soil and work it around the plant. If there are several plants in the pot, netting is a lot easier to place in the nooks and crannies between them. Some bent wire can be used to hold the netting down if needed, but it may be fine without this.
Q: Some of the cacti I have in pots clearly need slightly larger homes and I know that early June is a good time to do this, but how do I move them without getting stuck with the spines?
A: If the plants are small (no wider than an orange) you could use kitchen tongs to gently lift them from one place to the other. If they are larger or an unwieldy shape, fold a sheet of newspaper lengthwise three times and wrap this around the middle of the plant. This should prevent the spines from poking through. Hold the paper firmly but gently against the plant using a hand on each side to balance it and lift the plant into the new pot. With either method, it's still a good idea to wear gloves.
Q: I planted some hanging baskets which started out well but now they are drooping. What can it be?
A: Most of the potting soils you are likely to use are very hard to get wet again once they dry out, and drying out can happen very quickly. If this is the problem, take the planter down and submerge the soil in water in a bucket. Leave it there until you can tell that the soil has rehydrated (the basket will be a lot heavier) and then water more frequently. It can help when you are planting a basket to put a layer of plastic (maybe use the ones you can't avoid getting when you shop) under the soil. This will help reduce water loss due to evaporation. Poke some holes in this liner of course so that there is still drainage.
Q: So, I'm inspired to plant some herbs but do I have to dry them before I use them?
A: Most herbs can be used fresh or dried. Since water loss during drying reduces the size of the leaves, you usually need to use fresh herbs at 2 or 3 times the volume you would for dried herbs. Some, like thyme, dry easily--just rinse, pat dry, and put in an oven at low heat for a while. Check often so they don't burn. Crumble, remove stem bits, and put in a jar in a cupboard. Others, like basil, cilantro, dill, parsley, and chives lose a lot of flavor when dried so they are best used fresh. They can be rinsed, patted dry and chopped, or whole sprigs can go into whatever you are cooking--just remove the stems later like you would do with bay leaves. Dill can be chopped and frozen for later use. If you have too much parsley or cilantro at one time, they both make excellent pesto.
Q: I'm itching to get started with a vegetable patch. What can I plant this March?
A: Early this month you can still plant some cool season vegetables, like broccoli, head lettuce, kohlrabe, potatoes, cabbage, mesclun. Also, those that do fine here planted any time, such as beets, carrots, chard, turnips and radishes. Around mid-month, you can plant artichokes, chayote, corn, green beans, New Zealand spinach, and tomatoes. If you have a warm spot, you can plant cucumbers and squash. Vegetables that thrive on hot weather, such as eggplant, melons, peppers, and pumpkins will do best planted in April. March is also a good time to plant most herbs, either in pots, a herb garden, or interplanted with your vegetables. (Note: mint is typically invasive so does best in pots, and rosemary grows into a woody shrub so is a good candidate for a place in a sunny border.)
Q: Last year I saw what looked like giant white poppies around town. What are they and how would I grow them?
A: These Southern California natives are Matilija poppies (Romneya coulteri), also often called "fried egg poppies" because of the big boss of golden stamens centered on the white petals which can reach up to 9 inches across. When happy, this plant grows by underground rhizomes to form a thicket of up to 8 ft tall (although usually shorter) stems with jagged, gray-green leaves. It is happiest in full sun with good drainage, and needs no water once established, although it is OK with a little. It typically dies down in hot summer weather and the dead stems can be cut back in late fall or winter for late spring/early summer bloom. The Grow Native Nursery at the California Botanic Garden often has them for sale.
Q: Our sycamores lost a lot of leaves and are not looking well. What is causing this and is there anything we can do?
A: Our native sycamores, Platanus racemosa, suffer from a native fungal disease, sycamore anthracnose, which is very hard to avoid. Removing any fallen leaves along with dying leaves and twigs that may harbor spores is a start, and so is pruning to make sure that the tree is open--this helps avoid the humid conditions that the fungus revels in. The best time for this pruning is January and February. This is a hard condition to treat, but these actions, along with a good feeding in the spring should help.
Q: I'd like to cheer up my garden (and myself) with some spring color, and I was thinking of planting a lot of bulbs. When is the best time to buy them, and would I get a good effect with the cheaper versions?
A: Most bulbs are sold dormant--spring bloomers in the fall and summer bloomers in the spring. So now is a good time to order them and to plant the ones that flower in the spring. The cost of bulbs generally reflects the size of the bulb and therefore the number of flowers you are likely to get from it. However, if you want a mass planting of daffodils, for instance, you might consider buying the ones designated for naturalizing. These will generally be smaller bulbs with fewer flowers per bulb, but en masse will provide a good display.
Q: We'd lke to screen an eye-level eysore quickly. City rules prevent us adding a fence and growing a hedge would take too long. Any suggestions?
A: You might consider planting a row of young evergreen trees that already have a canopy at eye height. The branches would help obstruct the view and you could plant shrubs below to hide the empty space between the trunks. One possibility would be Prunus illicifolia, our native hollyleaf cherry, which is as tough as they come and can be kept as short as you like.
Q: I really like the yellow flowers and purple-blue berries that I've seen on mahonias further north in California. Are there native ones I could grow here?
A: Yes, there are quite a few species and hybrids, from ones that grow 10 ft tall to ground covers, that will do well in our area. One of the best is Mahonia "Golden Abundance", a hybrid developed years ago at the California Botanic Garden. This one grows upright to 8 ft tall and can be planted 4 ft apart to use as a hedge. The prickly, dark-green, holly-like leaves make a good barrier. Birds love the berries. Plant in full sun (although it will tolerate some shade it will flower less), water the first year to get established, and after that it does fine with regular or little or even no water. For a really prickly, grayish-leaved native with translucent red berries, you might consider Mahonia nevinii. It is endangered in the wild but available in nurseries. Mahonia repens does fine in light shade and is a good choice for a ground cover.
Q: My melons are ripening but some are showing signs of rot on the bottom. What can I do?
A: This is pretty common and there are several ways to prevent it: 1) train the vines up so the fruit is off the soil (you might have to put the melons in a sling to hold their weight), 2) put a piece of wood, a stone or something else under the fruit to keep it off the ground, 3) build a ridge of soil around the place where the stem emerges from the soil, about a foot or two out, and confine water to that area, 4) punch holes in several coffee cans, sink them in the soil in the root zone and use them to deliver water to the roots. These methods work for vining squashes as well.
Q: I planted an Arbutus 'marina' as a drought-tolerant tree. Will it need summer water and what can I do for the aphids it has developed?
A: Where Arbutus 'marina' evolved is unclear but it is thought to have Mediterranean heritage. It does best with regular (but not necessarily weekly, every two to four weeks should do depending on time of year and rainfall), moderate watering throughout the year and as with almost all trees, it's good to make sure that water reaches down at least 2 feet so that all the roots have access to it. If watering is shallow, the deeper roots can die and the plant will suffer. And of course, the water should cover the area from about six inches from the trunk to the outer tips of the branches. For the aphids, have you tried blasting them off with a strong jet of water? Encouraging aphid-eating insects and birds might also help with this.
Q: My family loves corn so we planted some this year. How will we know when to harvest the ears?
A: When the silks turn brown, the ears are close to being ready. Peel back the husk on an ear and puncture one of the kernels about two inches down. If the liquid is watery, the ear isn't ripe; if the liquid is gooey, you waited too long for perfection (but it will still be great in corn chowder or cornbread); if the liquid is milky, the ear is ready for eating! At this point, speed is of the essence: the sugars in corn kernels start to turn to starch as soon as you pick the ear, so for the sweetest corn, minimize the time from vegetable plot to cooking pot.
Q: My camellias bloomed profusely this year but the plants are getting a bit rangy and hanging too far down over the sidewalk. When can I prune them?
A: Camelliias generally flower quite well without any pruning but they can get a bit leggy as you have discovered, especially if they are in too much shade. Soon after flowering is the best time to cut them back a bit, so now is a good time to prune. (Camellias are dormant when in bloom and start into new growth after that). Cutting off the terminal buds will stimulate the growth of branches below them. You can actually cut off most of the previous year's growth to encourage a bushier plant. Pruning can be done in summer or early fall as well, and unwanted shoots can be removed anytime.
Q: Is double-digging a good idea?
A: "Double-digging", the practice of removing topsoil ( the first dig), loosening the subsoil and digging in soil amemdments (the second dig), and replacing the topsoil, used to be very common, especially for vegetable gardens. The modern consesus is that it is generally not a good idea because it tends to disrupt the natural layering and organisms in the soil, it's too easy to mix the topsoil and subsoil, it can lead to greater erosion, and it can release stored carbon into the air. It's also a lot of work! However, if the soil is badly compacted in the only sunny area you have for a kitchen garden, and you do this carefully, it can be a help, especially if you mulch the soil afterwards. For most beds, and even for vegetable ones, just adding compost regularly for the soil critters to pull down and the roots to use, gently aerating the soil with a garden fork, and watering regularly (making sure not to push out the air by walking on the wet soil) should keep most beds (and your back) in decent shape. And of course, raised beds are always an option.
Q: I'd like to create a flowering hedge and I love hibiscus. Would that work?
A: Yes, tropical hibiscus (Hibiscus rosa-sinensis) does well in frost-free areas in full sun (may need a bit of shade in very hot areas) and can be pruned into a lovely evergreen hedge, but it takes a bit more work than other plants. Hibiscus is a fast grower and blooms on new wood so if you don't prune, you will get fewer and fewer flowers. However, an overall pruning will slice up a lot of the large leaves, so if you decide to use the electric hedge clippers, consider doing one side each year which will encourage blooming but let new leaves have time to grow. A second method is more work but the hedge will always look good and bloom well. In June target about a third of the branches, evenly distributed throughout the shrub, and cut them back one or two feet into the shub. In July, do this to another third of the branches, and in August do the last third. This way you will keep them in bounds and have lots of flowers too. Note: the fancier varieties of hibiscus don't tend to make as dense a hedge, and giant white fly can be a problem.
Q: Most of the lemons on my tree look quite ordinary but a few of them are shaped really oddly with pointy bits. What has caused this and should I worry?
A: It sounds like the fruit is showing damage due to citrus bud mites. These suck sap from bits of the ovaries of the flowers as they develop. Odd-looking but not hazardous to your health or to the tree's. If there is a large problem, you could try treating the tree in June and October with one of the sprays based on vegetable oil. This should kill most of the bud mites but avoid killing the helpful predatory mites on the tree. However, if there are only a few of these peculiar lemons, I'd just leave the tree alone. (Note: there will be a photo of an affected lemon in the February newsletter.)
Q: I'd like to keep the poinsettias I bought to decorate the house. Any advice about doing that?
A: So, keep inside, plant outside, or toss? Poinsettias (Euphorbia pulcherrima) are frost tender, prefer acid soil, grow to 8 ft in the ground, and do not bloom well unless they get two months of pretty much total darkness at night in the fall. With care you can provide this indoors and keep them going for quite a while, but they do tend to drop the green leaves and start looking leggy. Darkness is hard to provide in an urban garden, so unless you enjoy a challenge, this is not going to be successful. However, I have seen some blooming in the occasional garden around here so no reason not to give it a try. If you do keep them growing, wear gloves when pruning as the milky sap of euphorbias can cause skin irritation. (By the way, poinsettias are not poisonous–that’s an urban legend.)
Q: I've noticed that a lot of tree trimming is going on at the moment. We have a large coast live oak that could do with a bit of care. Is now the right time to do that?
A: Live oaks should be pruned in the summer when their growth slows. Winter or spring pruning can cause them to produce "witch's brooms", wispy growth at the branch ends that are the result of a fungal infection. When you do prune, all the cuts should be made back to where the branch starts, as stubs may not heal and are likely to die back and cause rot problems.
Q: I planted some of our native yarrow (Achillea millifolium) several years ago. It has done well and slowly spread, but lately the center seems to be dying, although the outer bits seem just fine. What is wrong?
A: Actually, it's pretty certain that nothing is wrong, fortunately. Plants, like people, have a limited number of days on earth--since the plants in the center are the oldest parts they are most likely just reaching the end of their life. All you need to do is cut the stems down to about 6" tall and dig up the clump. Then remove the dead center and toss it in the compost, divide the healthy outer portions and replant them to start new clumps. Now is the perfect time to do this.
Q: I know we don't get enough natural outside chill for hyacinths, tulips or Dutch crocuses, but I'd like to plant some anyway. What do I need to do?
A: You are right that these need a cold period in order to bloom so put them in brown paper bags (not plastic) in a part of the refrigerator where they will be cold (but not frozen) for 6-8 weeks. Be aware that too much ethylene gas, which is given off by ripening apples (and bananas and pineapple), can cause the bulbs to rot or sprout prematurely, so keep these fruit in airtight bags. You can also sometimes buy prechilled bulbs and just plant them directly. Also, unlike the classic Dutch tulips, some natural species tulips do fine without a chill, and so do saffron crocus which bloom later (and you get to harvest the saffron!). You might also consider opting for some of the Tazetta narcissus varieties which tolerate our climate quite well--I have some paperwhites that have bloomed dependably for the last 20 years.
Q: I'd like to replace some of my Bermuda grass lawn with raised beds. How can I get rid of the grass?
A: Each bit of the Bermuda stolons or rhizomes left in the soil, as well as any seeds, can grow and once you irrigate your beds, they are very likely to do so and come up in the vegetables. Digging up all the area and sifting the soil is labor-intensive (I've done this so I know!) and you are still likely to miss some pieces. I personally avoid herbicides so you might consider solarization of the areas where the beds will go and for at least 2 feet around the perimeters of the beds to kill as much as possible of the Bermuda. Now is a good time as we will have hot weather for the next few weeks and solarizing takes 4-6 weeks. Remove the grass or mow it short (put the refuse in the trash). Water the area as that makes the heat penetrate better, and then right away put down a layer of clear UV resistant polyethylene over the area--1.5-4 mils plastic drop cloths are an option--weighing down the edges. There are likely to be bits of Bermuda lower in the soil that don't get killed, but most of the seed and the bits in the top few inches should be. After the solarization, be sure not to cultivate the soil or you may bring up bits and seeds that didn't get killed. The other alternative is just to resign yourself to continually removing the Bermuda as soon as it appears in your beds. If you are vigilant, eventually you should defeat it but it is likely to take quite a while (no method is instant). Landscape fabric covered with mulch around the beds will help control invasion from the edges.
Q: Now that we've been spending so much time indoors, I've increased my collection of houseplants which is great for my mental health. However, some have developed unsightly brown tips and edges to the leaves. How can I prevent this?
A: There are a lot of reasons this might happen: overwatering, underwatering, low humidity, drafts, too much fertilizer, high salt concentration in your tap water or a combination of some of these. First of all, find out what the preferred growing conditions for the plant are so you can narrow down the possible culprit(s). Then change one of the factors and see if the plant improves. If not, try the next possibility. Sometimes it's a hard slog to figure this out.
Q: I've been pruning the exuberant new growth on some of my shrubs to keep them in bounds and noticed that some of the new growth on my variegated ones is completely green. What should I do?
A: As soon as you see these, prune them out down to the place where they start. Green shoots are more vigorous than the ones with the variegated leaves--the plant will favor them and eventually you will have an all-green plant if you ignore them.
Q: I'd like to save seeds from my poppies to plant next year. What is the best way to do that?
A: Once the seed pods start to turn brown, you can cut them off and put them in a dry area in the house or garage on some paper to dry out completely. After a couple of weeks, you should hear the seeds rattling around when you shake the pods. At this point, you can cut off the top of the pod and shake the seeds out. Remove any bits of the pod and store the seeds in an airtight container out of the light. Another way to collect them is to use cheesecloth or old nylon stockings to form a bag around the pods and let the seeds mature on the plant and let the pods split open naturally. This is a bit more work but ensures that the seeds are ripe. When the pods open, cut them off and shake out the seeds. Let them dry out for a couple of weeks and then store them airtight in the dark.
Q: Now that we are supposed to stay at home because of coronavirus concerns, what can dedicated (or occasional) gardeners do to fill the time?
A: Well, the obvious starters are to go outside and attack the weeds that are now emerging with enthusiasm after the rain, trim the ground covers back from the paths, do a spot of pruning, and order seeds and plants online, but it's also an opportunity to reassess your garden. There's time to make a scale drawing of your lot and think about how you would like to change it: a new patio? a storage shed? some raised beds? a run for the dogs? a grape arbor? a native plant/pollinator area? a compost heap? the possibilities are many. After you have decided on your wish list and where you would like the items to be, you now have the time to go around the garden several times a day and make a record of where sun and shade fall at different times, where the wetter and drier spots are, where it's windy, what neigboring eyesores you would like to screen, and so on. This information will be key to making good choices about what and where to build and plant. For some help in creating the garden of your dreams, take a look at the links we have included under "Resources" above.
Q: What are the odd-looking grubs I've been finding?
A: These are beetle larvae. The photo that was sent showed fat little critters about an inch long with golden brown heads, dark gray hind ends, curled on their sides like a letter “C”. Although there are several different types of beetles whose larvae live in the soil, most of the grubs look similar and most eat roots. However, this is not a problem if there are only a few of them. if you find some in your pots or beds, you can just toss them out in some open space for birds to eat. I usually leave most of them alone since many are larvae of the beautiful, iridescent green fruit beetles that buzz around in summer, and I like those. The damage to my plants seems to be very small. No treatment is needed in a lawn if there are 5 or fewer per square foot (dig up a couple of square foot patches to check and then replant the sod). If there are more than 10, then the grass may be in trouble and you may see brown spots appearing in summer. Grubs don’t do well in dry soil, so water your lawn the minimum to see if that takes care of the problem. You might be able to add parasitic nematodes (a type of tiny worm) to the soil. Ask at your local garden center and be sure they are alive when you buy them. If these don’t do the trick, as a last resort, you can try applying a chemical in July or August next year. If you do use one, water it in to encourage the grubs to move up to the wet area. However, the number of grubs varies a lot from year to year, so postpone using chemicals until you are sure you have a persistent problem.
Q: What are some annuals or perennials that will seed themselves around my garden?
A: One of my favorites is Honesty (Lunaria annua) whose clusters of purple flowers are followed by fascinating seed pods. Where you have this one year, you will have more the next! Because it does so well in my shady garden, I collect the seeds and sow them around every fall. I also love the groups of small white daisies that feverfew (Tanacetum parthenium) produces from spring to fall. In a sunnier area, nasturtiums (Tropaeolum hybrids) make a colorful (and edible) carpet. And of course, the tiny white flowers of sweet alyssum (Lobularia maritima) spread with enthusiasm and attract lots of pollinators. In sunnier and drier spots, patches of our native fiddleneck (Amsinckia menziesii) wiil increase each year, producing hairy leaves and coiled stems of tiny yellow-orange blossoms.
Q: My tangerine produces a lot of flowers but hardly any fruit. What might be the problem?
A: Citrus tends to produce a lot of blossoms and a lot of these get fertilized and start to set fruit, which then drops. This can be due to a number of cultural problems. First, citrus are heavy feeders and do best if fertilized monthly, or twice a year if you use slow-release fertilizers. Second, keeping the area from about a foot from the trunk out to a few feet beyond the drip line evenly moist helps. Too much or too little water can be a problem: every week or so in hot weather, and every three or four weeks in wet weather. Third, excessive pruning can shock the tree. All that being said, about 80% of the fruit that starts out is likely to drop under the best of circumstances, but that usually still leaves a good-sized crop.
Q: How can I tell if my avocados are ready to pick?
A: Unlike a lot of fruits, avocados won't ripen on the tree. When you think the crop is about ready, pick a couple of avocados every few days and see if they ripen at room temperature in a week or two. When some do, you can assume most of the ones on the tree are ready to pick. If picked too soon, the fruit won't ripen and will be rubbery; if left too long, the oils start to taste rancid and the flesh will be dry. Left on the kitchen counter, avocados will be ready to use when they give slightly when you press them. If you have too many ripe ones, you can toss them in the freezer and use them later for guacamole.
Q: An animal broke several stems of my cane begonias a while ago, so I trimmed them and put them in water. Now they've developed roots and I'd like to plant them back in the garden. Is there anything special I should or should not do?
A: Roots that develop in water are somewhat different than ones that develop in soil, so you need to reduce the shock from going from total wetness to much dryer surroundings. Pot the cuttings up very gently and water them well. Cover with a plastic bag for a week or so to reduce water loss. Keep the soil consistently moist for a few weeks thereafter so that normal roots can form. Then move the pots outside in a sheltered location for a week or so and reduce watering a bit. Finally, move them into larger pots or into a garden bed that has similar conditions to the ones where the parent plants thrived.
Q: Recently I've seen a lot of spider webs spanning my garden paths and patio, and even across my driveway. Should I worry?
A: If the occupant is mottled brownish, with a body about 1/2" long, and sits in the middle with its legs drawn up (less of a target for its predators) it is most likely a common orb weaver (Neoscana oxacensis). These spiders will rush to the edge of the web if you disturb it to get away from you. They could bite if you provoke them and don't let them retreat, but they are not dangerous like black widows. Most eat the web each day and spin a new one so the webs usually are pretty debris-free. These, like all spiders, help to keep down the number of insect pests and, since common orb weavers are only present in the garden fom late summer to fall, I usually leave them alone if at all possible and just walk around them.
Q: I'd like to combine ornamental and edible plants in my garden beds. Do you have any suggestions?
A: Almost all food plants do best with quite a lot of sun, but many will tolerate some shade if you are OK with a smaller crop. Plant some genetic dwarf or semi-dwarf fruit trees and keep them pruned to about 8 ft tall so they are easy to harvest, and plant under and around them. Check out our April, 2019 newsletter for suggestions about vegetables that will do OK with some shade. For those that need full sun, like tomatoes and beans, you can grow them on structures like teepees or trellises in the midst of a sunny bed. Rainbow chard, red sorrel, variegated sages and thymes, artichokes, fennel, nasturtiams and many other plants are both good to eat and decorative. The key is too make sure that the plants in any particular area have similar light, watering, and fertilizer requirements.
Q: I have some very large pots and filling them with potting soil is going to be expensive and make them really heavy. What can I do?
A: You can fill up to a third of the space with something lightweight and then cover that with landscape cloth to prevent soil from moving down. You can use an upturned plastic pot, crushed aluminum cans, non-degradeable packing peanuts, broken styrofoam, or other similar items as long as they are clean and won't decay, so no wood or paper products. Be sure the drainage hole in the pot isn't blocked. After you put in the lightweight stuff and the landscape fabric, add the soil, water it in, and let that drain before adding your plants. Potting soils tend to sink somewhat because watering reduces the air spaces in the soil. If you plant first and then water, your plant may end up lower in the pot than you want.
Q: I have roses of one color growing in a mixed bed and just noticed some long, flexible canes with different colored flowers growing several feet away. What has happened?
A: Most roses are grafted onto a rootstock because this is an easy and efficient way to produce a lot of a particular variety for sale quickly. If branches sprout from the rootstock, the blooms that the suckers produce will be different from the top, grafted portion. Suckers arising from below the graft are easy to see and remove, but sometimes a root will send up a new shoot several feet away from the original shrub. You can dig down and remove this new plant and the root it is growing from
Q: What is a safe way to get rid of those healthy looking grubs I'm finding all over my garden?
A: Sounds like beetle grubs. Our September 2013 newsletter had a short article on them. A lot of these are larvae of those big, beautiful, iridescent green fruit beetles that buzz around later in the summer. I like them so I usually leave them alone. However, I replanted a very large pot last year and there were dozens so I just tossed them on the ground for the birds to find.
Q: My daffodil and narcissus flowers are long gone and the leaves are covering up the perennials and annuals around them. When can I cut them down?
A: Next year's blooms depend on bulbs or corms storing enough energy this year, and that is done through photosynthesis in the leaves. The best method is to leave them until they start to turn yellow and then cut them off. If they are really a problem, then you could tie them together loosely so they don't fall over. Some people fold them over and tie them in a bunch but the less light the leaves get, the less efficient they will be. This is true for other bulbs and corms such as chasmanthe, montbretia, gladioli, sparaxis, bluebells and so on. All do best if you let them die down naturally.
Q: My Mexican sage is looking very scraggly. How can I make it look better?
A: The old stems of Salvia leucantha can lose a lot of their beauty at the end of the year but it's easy to rejuvenate a plant. You'll notice a lot of new growth arising from the ground now and as soon as this is at least 6" tall, you can cut the old stems down to ground level. In a couple of months the plant will look healthy and bushy and soon it will be busy attracting butterflies and hummingbirds.
Q: A plant about a foot tall with clover-like leaves and yellow, conical flowers that close at night just appeared in my garden. Is it something I'd want to keep?
A: This is Oxalis pes-caprae (Bermuda buttercup, sour grass), a South African native that has naturalized in California. Some people love it, and others do not. It goes completely dormant in early summer and re-emerges in winter. It produces large quantities of small bulbs making it hard to get rid of completely once established. It can be pretty invasive so if it appears where it might smother other small plants as it spreads, dig it out as soon as you see it. If it volunteers in an area where that is not a problem, you might decide to leave it.
Q: Can I plant the poinsettias I bought outside?
A: Yes, but these Mexican natives tend to grow into largish, weak-stemmed shrubs and the new "flowers" are likely to be smaller than they were on the plant when you bought it. If you live here in Southern California and want to give it a try, keep the plant in bright light, out of drafts, and water it well when the top half inch of the soil dries out. In early March, cut all the stems down to about six inches and move the pot outside to a shady area for a couple of weeks. Then plant the poinsettia in a sunny, frost-free location and pinch out the stems occasionally to keep it shorter and fuller. Note: Some people are allergic to the milky sap these plants produce when injured, so it's a good idea to wear gloves when working with them.
Q: What's a good way to keep track of where my perennials are once they die down, and places where I've sown seeds?
A: One no-cost and easy way is to save a short, sturdy piece of stem and stick it in the ground to identify the spot. Another simple method is to use the cheap wooden skewers you can buy in packets of 100 at most markets. (If any of our members have additional suggestions, please send them along so we can share them!)
Q: What are some shrubs I could plant now that will provide berries for birds?
A: Mahonias have yellow flowers in late winter or early spring, followed by blue berries. Species range from groundcovers to 10 ft tall. Most like shade and average water, but desert mahonia, M. fremontii, takes sun and low water. Mahonia "Soft Caress" has soft leaves instead of the usual prickly ones. Red-flowering currant, Ribes sanguineum, takes part shade, and its pink spring flowers attract butterflies and hummingbirds. Bearberry, Arctostaphylos uva-ursi, is a tough, spring-flowering groundcover that will provide tasty (to birds) berries in the fall, as will other, taller, manzanitas.
Q: I have a garden bed that repels water. What can I do?
A: First check to see if the surface has become compacted which often happens if it is walked on or if large water drops hit the surface regularly, and sometimes just as the bed ages. In this case, just dig down with something like a hand fork and gently loosen the top few inches. Try not to mix up the soil as that can mess up the habitat for beneficial microorganisms. If the soil dried out at some point so much that it is repelling water molecules, you can try loosening the soil a bit and then wetting the surface gently just to the point of runoff, waiting a few hours, and repeating this several times. If there are a lot of small, dry, broken down leaves or stems covering the ground, they may be repelling the water before it reaches the soil so try removing them from an area and see if that helps. Over time, the fungi that normally break down thick layers of wood mulch can clog the air pockets so you might alternate types of mulch. Compost or other soil amendments can help to add material that attacts water too, and of course you can dig out the bed and replace the soil. Commercial soil surfactants or detergent solutions can have adverse effects so should only be used if nothing else works and then cautiously.
Q: How dangerous are Africanized bees? What should you do if attacked?
A: Colonies of Africanized bees are still quite uncommon, thankfully, but if one is around, it can be a problem, and some deaths have occurred. These honeybees look just like regular ones and generally will leave you alone. However, it takes less to make them feel threatened, and when they do, large numbers of them will chase the object of their ire for long distances. You should always act calmly around your bees but if a swarm does start to attack, the best defense is to cover your head and face and get inside away from them immediately. If you are not near a shelter that can be closed off, run in a straight line until you find one or the bees give up.
Q: Can I prune my Cleveland sage back now to encourage it to rebloom and keep it from smothering nearby plants?
A: The consensus is that these sages, such as the variety "Allen Chickering", bloom only once and that pruning should be carried out in the fall and winter. At that time, you can shorten stems by up to 1/2 to keep the plant from getting leggy. However, since new growth won't sprout from old wood, you should be sure not to cut back to leafless portions. A little careful pruning now just to reduce its encroachment on its neighbors shouldn't hurt the plant.
Q: I have noticed a number of volunteer trees sprouting in my garden. How can I tell what they are, and what is the best way to get rid of them if I don't want them?
A: Three of the most common volunteers have large featherlike leaves composed of a midrib with a number of leaflets: Shamel ash has 5-9 leaflets, European ash has 7-11 leaflets, and Tree of Heaven has 11 to 41 leaflets (and the leaves have an unpleasant odor when crushed). A fourth common volunteer is the golden rain tree which has even larger leaves that have branches off the midrib with leaflets growing along them so it has a "ferny" look. If you don't want the tree, just water the ground to make it easier to dig and remove the plant with as many of the roots as you can. Or just keep cutting it off at the base every week or so and eventually it will give up.
Q: Is it better to buy or make nectar for hummingbird feeders?
A: Chris Verma, owner of Wild Birds Unlimited in Claremont, says you should not buy liquid feeds because they have additives that can harm the birds. To make your own, bring one part ordinary sugar and four parts water just to a boil and then let cool. Do not add any dye. If you want to have something red on a plain feeder, tying a ribbon on it will do. Be sure to replace the nectar and clean the feeder every few days to avoid stuff growing in it that would harm the birds.
Q: There are brown areas on my camellia flowers. What is causing them? Could it be too much shade?
A: Camellias like shade and don't like being transplanted so I think you'd be fine leaving the plant where it is. Camellias are subject to "petal blight" fungus which is almost certainly what you are seeing. This is very difficult to control and anti-fungal sprays are of limited effect. The best method is to remove affected flowers and be sure to clean up all the ones that drop, including every single petal. These should all be tossed in the trash and sent to the dump. With luck, the problem will recede in a year or so, but it requires vigilance. The Camellia Society has more info at https://www.americancamellias.com/care-culture-resources/insects-and-diseases/camellia-petal-bligh
Q: I love tomatoes but have trouble digesting the seeds. Are there any seedless tomatoes?
A: Although our March speaker on tomatoes, Dave Freed, hasn't grown these, he did mention that seeds of a seedless hybrid can be ordered from the Totally Tomatoes website, and we found that plants and seeds are also available from Burpees.
Q: I have some very shady and dry areas in my garden. Are there any plants I could grow there?
A: Definitely one of the hardest areas to find plants for, but cast-iron plant (Aspidistra elatior) and butcher's broom (Ruscus asculeatus) do just fine in quite a lot of shade and have low water needs. Slow growers and insignificant flowers but require very little care other than removing dead leaves occasionally.
Q: My chives still have some green leaves but they have flopped over. What should I do?
A: Give the plants a crew cut by cutting off all the leaves, both dried and green, to about an inch long. New leaves will start sprouting in a few days.
Q: Can you grow strawberries as house plants?
A: Our November speaker, Julie Bawden Davis, says "Yes, indeed" and suggests trying "Seascape" or "Albion" in a sunny window. Fertilize the plants regularly and keep the soil moist.
Q: At the October meeting on composting, a member asked if you can use ashes in your compost.
A: Speaker Dave Schroeder has written to say that you can use small amounts of fire place or BBQ ashes in the soil or in the compost pile as long as you mix them in thoroughly, but that ashes shouldn't be added to a worm bin.
Q: A friend just divided his clump of Chasmanthe and gave me some of the corms. How should I treat them?
A: Chasmanthe floribunda, African flag, is a member of the iris family. Plant corms about 3" deep in groups in light shade in well-drained soil. Plants are dormant in summer. Leaves appear in late fall, growing 3-4 ft tall, and the arching sprays of orange and yellow, thin, tubular flowers appear in early spring. A favorite of hummingbirds. More detailed growing information can be found at https://www.pacifichorticulture.org/
Q: Do you really need to wash and sanitize containers to reuse them?
A: The counsel of perfection is “yes” so that you don’t pass along any infectious material they may contain. [But I admit I usually just wash them out with water (unless the previous plant was ill) and have never had a problem.]
Q: Can you reuse potting soil?
A: Again, ideally no, you should spread it around and dig it into the ground somewhere (unless the plants were ill). However, I’ve left the soil in some very large patio pots for several years, just changing out the plants and adding fertilizer, and the plants have done well.
Q: Is there a way to kill grasshoppers without harming beneficial insects?
A: This is very difficult, as pesticides kill them all. The good news is that serious grasshopper invasions generally only occur every 8-10 years (although they can last 2 or 3 years). The following may help, but since grasshoppers are very mobile, they can migrate into your garden from other places outside of it.- Grasshoppers lay eggs in the soil, so tilling the surface 1-2 inches a few times in late summer, fall and winter may reduce the number that develop.
- The young hoppers like to live in areas of dense plant growth where spiders, blister beetles robber flies, and suchlike prey on the eggs and nymphs, so arrange to have a few areas like that.
- Grasshoppers prefer uncultivated, weedy, grassy areas, so if you have an out of the way spot, you might let it go (but keep it healthy) and hope the pests think of it as prime real estate compared to your weeded beds.
- Some birds eat young grasshoppers, so provide some perches in the garden. (Coyotes eat grasshoppers too, but you may not want to attract them!)
- Among vegetables, they generally give tomatoes, squash and peas a miss, but delight in lettuce, carrots, and beans and onions. Putting row covers over your vegetables can reduce the damage. Hungry hoppers can eat through fabric and plastic, so consider using metal window screening. Be aware, though, that covers` may reduce insect pollination of your crops, so you may need to do some hand-pollination.
Q: Poinsettias — plant outside or toss?
A: Poinsettias (Euphorbia pulcherrima) are frost tender, prefer acid soil, grow to 8 ft in the ground, and do not bloom well unless they get two months of total darkness at night in the fall. Darkness is hard to provide in an urban garden, so unless you enjoy a challenge, toss. If you do grow them, wear gloves when pruning as the milky sap of euphorbias can cause skin irritation. (By the way, poinsettias are not poisonous–that’s an urban legend.)
Q: Last year’s seed packets — use or toss?
A: Seeds don’t stay alive forever, but neither do they all expire immediately at years’ end. Like people, the ones in a packet vary a bit in life expectancy. If you keep your packets in a cool, dark, dry location, you can expect to get good germination for several years. Here are some approximate times (years in parentheses): corn (2), lettuce (6), beans (3), cucumber (5), eggplant (4), kale (4), melons (5), onion (1), peas (3), spinach (3), tomato (4), radish (5). If you have older packets and are worried about poor germination, plant more thickly than normal and remove any extras.