Just a cool drink will do for now
THIS YEAR’S exceptionally late rains are making for a splendid spring both in the garden and in the wild. But from now into late fall, gardeners need to get serious about irrigation. Of course, if you are growing mostly natives and other tough Mediterranean-climate plants that need little water once established, you can relax.
Slow and sure
Most plants are happiest when roots are deep enough to find moisture between irrigations (18 inches is usually deep enough). Plants with most of their roots in the upper few inches are likely to suffer on especially hot days, and a soil that stays too wet invites disease. It’s best to water slowly and deeply. Then wait a few days, even a week, until irrigating again. There are special low-flow sprinkler nozzles that put on water more slowly so it doesn’t run off (invaluable on slopes) but you can also water a bit, wait and water some more, giving puddles time to soak in. It’s not a good idea to quickly change watering habits in the middle of summer but start now and you can wean plants from too- frequent irrigations.
What to plant when
It’s not the best time to plant water-thrifty things such as our own natives because irrigating the young plants in summer gets dicey, and you can kill them with kindness. Autumn is the better time, as it is for many shrubs and trees.
But subtropicals such as coral trees, hibiscus, banana, gingers and bougainvillea are best planted right now as the weather warms. They need lots of water, but that’s the price you pay for flashy flowers. You can also plant camellias, roses, gardenias and other plants that need regular irrigation. And you can plant the many perennial flowers and foliage plants available at nurseries right now. At first, water them once or even twice a day if necessary. After a few weeks you can water them less and less.
Summer flowers ...
Obviously you don’t want to be blowing money on plants that are about to pack it up and call it quits, so look for those that have a whole season ahead of them, such as ageratum, celosia, bedding dahlia, gloriosa daisy, marigold, petunia, portulaca, verbena and zinnia. In the shade, try bedding and tuberous begonias, browallia, caladiums, coleus, impatiens, mimulus and forget-me-not.
... and summer savories
Now that the weather is warm enough, even near the coast, you can plant the big tomatoes called “slicers,” those sandwich-smothering giants, and they will grow and fruit quickly. Remember to plant the young plants deep, removing lower leaves so only a few stick out of the ground. Roots will form along the stem and plants will need less frequent irrigation. Tomato hornworms may already be on plants put in last month but the young, green caterpillars are difficult to spot unless you first spritz the vines with water, which makes them move and shake.
Other vegetables to plant now include beet, carrot, chayote, cucumber, leaf lettuce, melons, mesclun mixes, New Zealand spinach, onion, peppers, pumpkin, radish, squash, sunflower and Swiss chard. Don’t forget summer herbs such as basil. Peas that are finished should not be pulled out but cut off because their roots add nitrogen to the soil. As the leaves on onion and garlic plants begin to brown this month, stop watering. When about half of the foliage has slumped to the ground, gently bend over the rest to hasten the curing of the bulbs.
Thin fruit, plant citrus
For the best quality, thin young deciduous fruit so that they are far enough apart -- 5 to 8 inches for apples and peaches; 4 inches for plums and apricots. Less fruit means each tastes better and gets bigger. If trees are covered with young fruit, remove more since there is no way you can use it all. If you forgot to spray for peach leaf curl, rake up all the fallen, infected leaves and send to the dump.
It’s still a good time to plant citrus. Whitewash bare trunks with thinned latex paint (50-50) to protect young bark from sun scald. Make sure new citrus are adequately watered. Older citrus are less needy and may actually resent too much. Protect trees from snails and ants with barriers.
Mulch month
To conserve moisture and cool the root zone, apply woody organic mulches around trees and shrubs. The best are shredded limbs and foliage that are free from some cities or from tree trimmers. You can sometimes get similar shredded mulches from topsoil purveyors. Mulches should be heavy enough to not float or blow away, but those pebbles and chunks of bark make poor mulch because they provide hiding places for slugs, earwigs and sowbugs.
