I have been appreciating the flowers and vigor of my garden, as if it’s the first spring I’ve ever experienced. Everything, from Iris to oaks has seemed more alive, more beautiful, more giving this year. As wildflowers fade and the regular heat of summer sets in, it’s still a busy garden month. May is also a busy human-calendar month. Just do your best and remember how forgiving and resilient our plants are. And remember, Master Gardeners and the entire UCCE/IPM website are here to help.
Planting: Finish up spring planting in the ornamental garden before hot weather arrives. Almost everything can be planted now, especially early in the month. Bulbs, tubers, and corms to plant are dahlia, gladiolus, and tuberose. Succulents are fine to plant now too, as are avocados, citrus, bougainvillea, and other frost sensitive plants. Summer color can liven up both the ornamental and edible gardens. Species to plant now include zinnia, marigold, petunia, sunflower, cosmos, and impatiens.
Vegetables to plant now include tomatoes, peppers, basil, eggplant, summer squash and tomatillos. Don’t worry about some shade in your edible garden. Many summer garden vegetables do fine if they get at least six hours of sun a day, which is just about half a day. Heat lovers to plant in the full 14 hours of sun we can expect are winter squash, melon, okra, beans, and corn. Why not try a three-sisters garden of corn, beans, and squash? To be traditional, first bury a fish head, or simply make sure your garden soil is rich with life. How can you tell? There should be earthworms, perhaps some beetles, and a good “earthy” smell. If you have an established garden, plan on caring for your soil routinely by adding straw, compost and composted manure or store-purchased amendment. If your soil is healthy, your plants will need far less pest and disease management, making the garden healthier and easier to manage.
Maintaining: Check your watering system and adjust as the weather warms. Your new transplants will need to be supplied with water on a regular basis through late spring and right into summer. Don’t expect even low-water-use plants to survive on no water during their first year. Deep water stone fruit, apple, pear, and nut trees. For established gardens, the top several inches of soil can dry out for almost all plants in the well-mulched garden and in lawn. Many people over water their lawns, especially in late spring. This encourages disease and insect problems.
Prune spring-blooming shrubs like camellia, lilac, and hydrangea as they finish flowering. Pinch back fall-blooming chrysanthemums until July. Deadhead roses (remove old flowers) to encourage repeat blooming. Trim off suckers from the base of roses and from trees and take out any dead branches now that trees are fully leafed out. Thin your nut and stone-fruit trees when the fruit are small to improve fruit size and quality. How much fruit will you realistically consume? Thin, and then wait a day or two, and thin some more. Branches may break if they are overloaded with fruit. For young trees less than five years old, allow only a few fruits to grow to maturity so the tree can put more energy in root and shoot growth. Cage young trees against ground squirrels and deer in the foothills and mountains.
Continue with weeding. Add compost and/or mulch if you haven’t already to your planting beds. Keep wood mulch at least six inches away from tree trunks. Raise the mowing height for all types of grass to shade out weeds and keep roots cooler.
Monitor the edible garden for common warm season insect pests: earwigs, aphids, slugs, snails, and grasshoppers. Blast soft-bodied insects like aphids with a stream of water. Insecticidal soap is a good all-purpose insecticide for many insects, and it doesn’t kill as many beneficial insects as broad-spectrum powders and sprays do. Try to tolerate some damage, to feed garden friends like birds, spiders, lacewings, ladybugs, assassin bugs, lizards and praying mantis. Hand pick tomato/tobacco worms, hoplia beetles on roses, snails, and slugs. Root cage and cover gardens to exclude rodents. Leave rolled newspaper traps or put a little oil into opaque bottles and leave them laying sideways under garden plants to trap earwigs and other beetles. The traps need to be put in the waste every morning until the population is diminished. Control scale (they appear as little bumps on stems of citrus, bay, and other plants) with summer horticultural oil. You may need to repeat application in June. Follow package instructions to avoid harming your plants.
Fertilize your container plants now. Once a year is usually enough for most containers. Once every three years may be all that is needed for California native plant containers. You may never need to fertilize your succulent and cactus. Fertilize azaleas, camellias, and gardenias with fertilizer labeled for them. Fertilize citrus with fertilizer labeled for them. Citrus in containers need to be fertilized at least once a month during their blooming and growing season. They’ll live without it, but may not produce much, if any, fruit. Citrus in the ground should be fertilized this month and then not again until next year. Fertilize your warm-season lawn and groundcovers with an all-purpose product to promote vigorous growth and help prevent weeds. If you haven’t already, fertilize your roses.
Conserving: Don’t disturb your bee nesting and bird houses. Observe your trees before having the tree trimmers come to make sure you’re not disturbing an active bird nest. Leave a little radish, mustard and broccoli blooming in the edible garden until seed set to support pollinator insects. Consider adding a new plant for the wildlife. Do you have room for a quail bush, mulefat or California fuschia? Do you have room for yarrow, California buckwheat or native (these have pink and white flowers, not yellow or orange flowers) milkweed? Can you dedicate a space in the garden that is less manicured? This will support the greatest diversity and number of native bees, beneficial insects, lizards, toads, and birds. As we become more active this year than last, don’t forget the joy and serenity of a cared-for garden.
The Master Gardeners will be live to answer your questions at two upcoming events: May 1, 11 a.m. to 2 p.m. at Ace Hardware in Visalia; and May 8, 10 a.m. to 2 p.m. at Luis Nursery in Visalia. You can contact them at 559-684-3325, or visit their web site at ucanr.edu/sites/UC_Master_Gardeners.