Gardening Tips for May


By Peyton Ellas
UCCE Master Gardener
Whether a good rain year or a bad rain year, one thing we can count on in May is the change from spring to summer. The nights are still cool, and plants should still be in their glory of growth. Not everything blooms in spring; in fact, in a balanced garden, some plants are just coming out of dormancy, preparing to bloom in August and September. But it often feels like everything is happening at once, including the work. Take a breath, schedule a little work here and there. And don’t worry if you don’t get to everything. Generally, any garden chore can wait a month or a year. But for those of us who love working outside as much as we can this month, here’s a guide on things to consider:
PLANTING: We are finishing planting of ornamental perennials, shrubs and trees. We can still plant, but we better have our watering system ready to go from day-of-planting; we’d better have a good layer of mulch to keep those roots cool, and we’d better have helpers lined up for when we go on vacation and the irrigation controller malfunctions. Wait until cooler weather of autumn for finicky low-water plants like manzanita and ceanothus if you have clay-type soil. Ornamental grasses, lantana, yarrow, some types of sage and any frost-tender plants can be planted this month. 
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May is also a good month to plant heat-loving vegetables and herbs. Examples include basil, beans, corn, eggplant, melon, okra, squash, tomatoes, and peppers. Plant peppers, heirloom tomatoes and eggplant on the north side of taller vegetables like corn, pole beans and hybrid tomatoes to keep the fruit from sunburning. If you planted early in the spring, planting a second crop in May, or even June, can extend your harvest into fall. Edible heat-loving annuals grow quickly in warm soils. Just pay attention to pests. 
MAINTAINING: You’ll most likely need to start adding water to the ornamental garden, if you didn’t have to do it in April. Monitor your water to avoid adding too much, and work within your district’s regulations to deep water everything, especially trees and large shrubs. The top inch or so of soil should dry out between watering cycles. For established gardens, the top several inches can dry out for almost all plants in the well-mulched garden. Many people over water their lawns, especially in late spring. This encourages disease and insect problems. Also, raise the mower height to shade out weeds, and mow in varying patterns.
Many insect pests can attack the edible garden during warm weather, so regular observation and quick action are called for.  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, in order to feed garden friends like spiders, lacewings, ladybugs, assassin bugs, praying mantis and birds. Hand pick tomato/tobacco worms, hoplia beetles on roses, snails and slugs. Root cage and cover gardens to exclude rodents. Leave traps like rolled newspapers or bottles with a little oil for earwigs and other beetles. The traps need to be put in the waste every morning until the population is diminished. Control scale (they appear like little bumps on  stems of citrus, bay, and other plants) with summer horticultural oil. You may need to repeat application in June.
Plants to prune include spring-blooming shrubs when they finish blooming (or treat yourself or your mom to a house full of bouquets) like lilac (native and exotic), camellias, hydrangea, wisteria, clematis, native sage and, if you must, manzanita and buckwheat. Pinch back fall-blooming chrysanthemums until July. Cut back vigorous vines like grapes anytime during the growing season, especially if you don’t care about fruit. Deadhead (remove old flowers) roses 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. 
Continue to remove weeds. Does it ever end? Yes, in July, I would say. For a few months.
Thin your nut and stone-fruit trees when the fruit are small to improve fruit size and quality. How much will you realistically consume? Thin, and then wait a day or two and then thin some more. Branches may break if they are overloaded with fruit. For young trees, less than five years old, allow only a few fruit to grow to maturity so the tree can put more energy in root and shoot growth.
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Fertilize your container plants now. Once a year is usually enough for most 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 ground-covers with an all-purpose product to promote vigorous growth and help prevent weeds.  If you haven’t already, fertilize your roses. During drought years, fertilizing only once a year or every other year is recommended.  When in doubt, don’t fertilize. Top dressing with compost and then watering in can be done year-round as a natural amendment. 
CONSERVING:  Don’t disturb your bee nesting and bird houses. They may be in use!  Observe your evergreen trees before having the tree trimmers come to make sure you’re not disturbing an active nest. Leave radish, mustard and broccoli blooming in the edible garden until seed set to support pollinator insects. Consider adding a new plant for the wildlife, not for you. Even a tiny garden can probably make space for a native yarrow, a small buckwheat, or a bit of western columbine (Aquilegia formosa). Try to tolerate even the creepies like spiders and snakes. I love spiders and I like snakes just fine, especially the ones that eat gophers.  It’s okay to have some imperfection. Just say it’s your wildlife conservation area. 
Finally, don’t forget to enjoy the out-of-doors during the last hurrah of spring. Warm long days, flowers and fragrance, pollinator and other wildlife activity. It’s a great month to be in the garden!
The UCCE Master Gardeners will be available to answer your gardening questions at the Farmers Market in the Visalia Sears parking lot on Saturdays from 8 a.m. to noon, or at these upcoming venues:
Sat., May 12 – Exeter Chamber of Commerce Garden Tour from 9 a.m. to 2 p.m.
Sat., May 12 – Luis Nursery Plant Clinic, Visalia
Sat., May 19 – Orchard Supply Plant Clinic, Hanford, from 10 a.m. to 1 p.m..
Sat., May 19 – Orchard Supply Plant Clinic, Visalia, from 10 a.m. to 1 p.m.
Sat., May 26 – Bravo Lake Berry Tasting from 8 a.m. To noon at Woodlake Botanical Gardens 
To contact the Tulare/Kings Master Gardeners, call 559-684-3325, e-mail or write to 4437 S. Laspina St., Ste. B, Tulare, CA 93247.
– This column is not a news article but the opinion of the writer and does not reflect the views of The Foothills Sun-Gazette newspaper.