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.