A shower of opportunities

DESPITE THE UNUSUALLY late storms, spring has arrived -- and with it all of those April gardening opportunities including planting tomatoes and seeding lawns. Be sure to set aside time to smell the roses and other flowers -- at home and at botanic gardens -- because everything’s in bloom.

This is also the season for garden tours, including the Garden Conservancy’s impressive statewide and local Open Days program (www.gardenconservancy.org). Let’s just hope none will get rained out.

Time for tomatoes

Now is the time to plant tomato vines, unless you live within a few miles of the beach. Those near the coast often wait for warmer weather in May, and even then plant early kinds that survive in cooler weather, such as ‘Early Girl.’ The rest of us can chose from new or heirloom varieties -- those with disease resistance are less likely to succumb to the many tomato troubles (on the plant label, look for VFN, which stands for verticillium and fusarium wilts and nematodes, or something similar).

Plant the young nursery tomatoes deep -- pinch off the lowest set of leaves and plant so only the remaining leaves are above ground. Roots will form all along the buried stem, making the plant stronger and helping it forage for moisture between irrigations. Stake plants or grow them in a large cage (at least 5 feet tall). Remember, they need full sun but little fertilizer and not too much water. After the first few weeks, space irrigations as far apart as possible. Too much water or fertilizer makes for lots of growth but few tomatoes. Some coastal gardeners water once a week or less.

And the runners-up

While tomatoes top most gardeners’ lists of summer vegetables, they are only the very tip of the edible iceberg. There are tomatillos, the tomato’s close kin, and peppers, which many find even more useful in the kitchen (and they are certainly easier to grow). Sweet corn has its share of fanatics, but it takes up lots of space (it must be grown in blocks of 24 plants or more for complete pollination). This month, you can also plant lettuce, carrots and other salad fixings, though unfortunately it is difficult to grow them so they ripen later along with the tomatoes. Beans, cucumbers, melons, pumpkins, squash and sunflowers also can be planted now. And to go with those tomatoes, make sure to plant basil or cilantro, two tasty annual herbs.

Best time to plant citrus

Citrus are best planted this month, when the weather is warm but not too hot. Every Southern Californian should have a lemon tree, and at least one orange tree. Lemons are a cook’s best friend and some citrus fruit can hold on a tree for what seems like months. Valencia oranges, for example, are the champion hangers-on, becoming sweeter and sweeter the longer they’re allowed to ripen on the tree (at least up to a point, when they begin to dry out).

Plant citrus a little high -- about an inch of the root ball should remain above ground -- and be sure to use extra soil to mound up a watering basin around the plant. Trees will need to be irrigated frequently for the first year, and lightly fertilized twice a month, because that’s what they received at the growers. Later, they will need surprisingly little water and little or no fertilizing if the fallen leaves are left on the ground as a mulch.

Rose renewal

The best bloom on roses is the first, which happens sometime this month, though there is a fall bloom that can rival it. Bushes will bloom many times in between if the old flowers are promptly cut off after they fade and if the plants are then fertilized after every round of bloom. Try to make cuts just above a healthy, outward-facing, five-part leaf, so the new sprouts will be thick and strong and grow away from the center of the plant.

Watch out for tiny so-called rose slugs (actually sawfly larvae) that emerge from the ground and crawl up stems, peppering leaves with little holes. Catch them early and often and they can be controlled organically with a horticultural paraffin oil spray that smothers (not poisons) larvae. You may need to spray every two weeks well into summer to keep this pest under control.

Rampant bougainvilleas

Gardeners from other idyllic climates are amazed at how well bougainvilleas grow throughout Southern California. If the plants are doing a little too well in the garden, it’s time to take the long-handled pruning shears to them. Cut branches back quite a bit if necessary, or just a little, and they’ll quickly recover in the warming weather. Make sure you wear thick gloves since bougainvillea thorns are beyond wicked.

Sow or sod lawns

Now is the time to try a patch or to repair bald spots on lawns. Buy chunks of sod at a nursery and splice them into cut-out sections of the old lawn. Or lightly cultivate the bare soil and sprinkle new seed, barely covering the tiny seed with an organic mulch. Keep seed or sod moist until it becomes established. It’s also the ideal time to seed or sod entire lawns.

If Bermuda lawns were over-seeded last fall for winter green, start mowing lower to encourage the shorter Bermuda to green up for the warm summer ahead.