May is a lively month in our Central Valley. Cool nights, hot days, rain, bright blue skies, browning fields and hills as the non-native annual grasses seed and die. Wildflowers may continue. You may even have some plants in your garden that are just waking up from winter dormancy. Our summer heat allows us to have many great plants from California and elsewhere that really come into their own with hot days and warm nights. They wait to start really growing until they know more or less for certain that there will be enough heat for them. The days grow longer and signal to them the time is right. With all this garden action, we can expect to be out of doors much of the time, enjoying the last of spring and there can be plenty to do even in the low maintenance garden.
PLANTING: Finish up our spring planting in the ornamental garden before hot weather arrives. You can plant almost any species, but those that don’t like a lot of summer water may fare better if you hold off planting these until fall. Examples are rockrose, rosemary, ceanothus (California lilac), flannel bush, manzanita, bush lupin, white sage and most cacti. Succulents are fine to plant now, as are most other plants.
In the edible garden, plant citrus, avocado and any vines and other fruit trees. It is also a great month to plant tomatoes, peppers, basil, eggplant, summer squash and tomatillos. These heat-lovers do best in six-to-eight hours of sun a day. Don’t worry about some shade in your garden. In the Central Valley and low foothills, some shade is actually a good thing. Heat lovers that can take more full sun are winter squash, melon, okra, beans and corn.
MAINTAINING: If you haven’t yet, make some time early in the month to repair irrigation leaks and upgrade your sprinkler or drip irrigation system. Test your controller, maybe even consider upgrading to one of the smart timer systems, which have become quite affordable in recent years and easier to find in most garden centers. They can work with your smartphone and gather weather data to adjust the watering schedule and help save water and your time, since you don’t need to keep adjusting your irrigation.
Top dress with compost and/or mulch if you haven’t already. Bare dirt is not healthy for plants. It encourages die-off of micro-organisms in the top few inches of the soil, allows water and wind-caused soil erosion and threatens fine roots near the soil surface from burning and drought. Weather rock, gravel or organic (bark or leaves), mulch is part of a healthy, modern garden.
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.
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.
Prune spring-blooming shrubs as they finish flowering. 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. 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 fruits to grow to maturity so the tree can put more energy in root and shoot growth.
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 ground-covers with an all-purpose product to promote vigorous growth and help prevent weeds. If you haven't already, fertilize your roses.
I did say this is a lively month for gardening, right? That’s a long list, but remember to breathe, enjoy the day and your garden, and don’t worry overmuch if you don’t get everything done. We should remember gardens are for our enjoyment and for the benefit of the rest of the organisms we share this space with. It’s not a battle, although sometimes it can easily feel that way (more weeds? Really!?) Enjoying your garden with a bit of humility is a big part of practicing conservation: recognizing the part we play in a larger system, one that we mostly don’t understand.
CONSERVING: Don't disturb your bee nesting and bird houses. They may be in use! Observe your trees before having the tree trimmers come to make sure you're not disturbing an active bird 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, a sage, or a bit of western columbine (Aquilegia formosa). This year I’ve noticed the hummingbirds really enjoying my bladderpod bush, which I appreciate for its cheery yellow flowers in winter but did not realize it was used by hummers too.
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Finally, consider supporting and visiting your local conservation areas. We can learn a lot from plants growing in more wild settings, even if we don’t want those exact species in our gardens. Notice how plants cooperate and compete, how well they tolerate damage and even fire, survive flood and drought, wind, insects, and even humans.
The UCCE Master Gardeners will be available to answer your gardening questions at the following venues in May:
Thursday, May 9, 2019, 4:30 to 9:00 pm, Farmer's Market in Hanford
Saturday, May 11, 2019, 9:30 am to 3:30 pm, Mooney Grove Park, Visalia, TC Museum Main St. Jamboree
Saturday, May 23, 2019, 8:00 to 11:30 am, Porterville Farmer's Market at Sierra View Hospital
Saturday, May 25, 2019 - 8:00 am to Noon, Woodlake Botanical Garden Berry Tasting
You can also find us every Saturday from 8-11 am at the Farmer's Market in the Visalia Sear's parking lot on Mooney.
For answers to all your home gardening questions, call the Master Gardeners in Tulare County at (559) 684-3325, Tuesdays and Thursdays between 9:30 and 11:30 am; or Kings County at (559) 852-2736, Thursday Only, 9:30-11:30 a.m; or visit our website to search past articles, find links to UC gardening information, or to email us with your questions: http://ucanr.edu/sites/UC_Master_Gardeners/
Visit us on Facebook at: https://www.facebook.com/mgtularekings14/