May Garden Almanac
May brings the Planting Moon. If you did not finish your spring planting last month, it’s a safe bet the weather will be with you this month: balmy and sunny. This is the month to get warm-season, summer vegetables in the ground, tomatoes, peppers, eggplants, and melons. Not only are days warm, but nighttime temperatures and soil temperatures will now be kind to and encourage the fruiting vegetables.
Annuals: Summer annuals can be planted now. Petunias and calibrachoas will need a bit more water than celosia, cosmos, portulaca, and spurred snapdragons which can tolerate dry soil once established. If you plant alyssum, nasturiums, and California poppies, keep in mind that these annuals are self-sowing and will come again and again to the same area of the garden in years to come.
Perennials: Deadhead perennial flowers as they fade; this will give the plant the energy to keep blooming rather than produce seed. Stake tall and sprawling perennials such as delphiniums and dahlias now before they become top heavy with blossoms. Keep an eye out for pest insects; a strong stream of water will knock aphids and whiteflies from plants. Release beneficial insects like lady bugs and lacewings into the garden to control insect pests.
Lawns: Set irrigation timers for early morning to conserve water. Warm weather starts the season for white grubs (beetle larva) under lawns. These grubs have a brown head and white body and curl into a “C”-shape. They eat lawn roots and cause patches of dead turf. Apply a grub control now before the damage is done.
Vines: Prune frost-damaged vines if you haven’t already. Train new tendrils and vining branches up trellises and arbors.
Roses: Control powdery mildew by washing off foliage with a stream of water early in the morning. Use a canola-based horticultural oil to control powdery mildew. Control snails and slugs with organic iron phosphate bait.
Shrubs: Prune away faded flowers to direct plant energy into new flowers and growth. Add a 2-inch layer of mulch around shrubs to conserve soil moisture and keep down weeds; keep the mulch back from trunks and stems. Feed azaleas and camellias with an organic acid fertilizer now that most blooms have passed.
Trees: Add 2 inches of aged compost mulch around the base of trees to improve soil texture and add nutrients. Deep soak trees every 10 days during the growing season. Irrigation will carry the nutrients in compost mulch deep into the soil.
Vegetables and herbs: It’s warm enough to safely plant basil, dill, oregano, sage, thyme, and sweet marjoram now. It’s weather-safe to plant the most tender vegetable crops now – peppers, squash, melons, and okra. Add a 1- to 2-inch layer of aged-compost mulch around vegetable and herb plants to keep weeds down and conserve soil moisture. A strong stream of water will wash away infestations of aphids and whiteflies hiding on the undersides of leaves.
Fruit trees: When fruits are about 1-inch in diameter, apply an organic granular fertilizer around the base of the tree. Add a 2-inch layer of aged-compost mulch around the base of the tree but keep it back from the trunk. Early fruits such as apricots are ripe when they fall into your hand with a gentle twist.
Native plants: Native penstemons, sages, monkeyflowers and buckwheats will be blooming now. Ceanothus and manzanitas in the garden can be pinched and pruned this month to encourage repeat blooms. As native annual wildflowers fade from the garden toward the end of this month, don’t pull them; let the seedheads ripen for foraging birds. Quail are fond of lupines and native clovers. Mourning doves like the seed of red maids and California poppies.
Nature alerts: Hillsides will be gold with California poppies now; a backdrop for blue lupine, Mariposa lily, Indian paintbrush, buttercup, shooting star and spring vetch. Be on the lookout for deer with new fawns this month. Carry a flashlight at night: skunk, possum, and raccoon can be found in areas of undergrowth and near open water. Noisy jays and ravens will be building nests now, as will hummingbirds and pileated woodpeckers.
Kenwood weather averages: Temperature: Average high 75°F, average low 48°F, mean 62°F; average precipitation 1.28 inches; record high 104°F (1950), record low 31°F (1950). Sunrise and Sunset: Sunrise on the 1st 6:14 a.m., sunset on the 1st 8:01 p.m.; sunrise on the 31st 5:49 a.m., sunset on the 30th 8:27 p.m. Moon: Full on May 3; last quarter/waning on May 11; new on May 17; first quarter/waxing on May 25.
Steve Albert is the author of The Kitchen Garden Grower’s Guide available at Amazon.com. He teaches in the landscape design program at the U.C. Berkeley Extension. He lives in Oakmont.