By Calvin Finch, Conservation Division, Manager, Water Resources & Conservation Dept., SAWS, and HorticulturistLANDSCAPE GARDENING TASKS FOR APRIL
April is the first month of the South Texas gardening summer. The weather has stabilized and we need to take steps to prepare the landscape for the challenge of summer.
Somewhere around the middle of the month will be the peak bluebonnet display. Poppies, primrose, larkspur, verbena, columbines, coreopsis, and other blooms will also make a good show. Enjoy the blooms but remember that if we want the naturalized flowers to reseed for next year they must be allowed to mature and release their seed. Tolerate the unattractiveness of wildflowers past their prime for the promise of bloom next year. Delay mowing wildflower patches until late May or early June.
With the warm weather and some rain the lawn grass will finally green up. Keep it mowed to control the maturing winter weeds. If they form seed-heads you can expect to have them back again next year. Wait until you have mowed real grass twice before you fertilize. Only then will the St. Augustine, zoysia, Bermuda, and buffalo grass be able to utilize the nitrogen. That date is usually late April.
Iron chlorosis (yellowing) in St. Augustine grass is common in April. The grass is not adapted for alkaline soil and has trouble taking up iron from the relatively cool soil. In most soils, the grass will overcome chlorosis in May or June, but it can be treated with a foliar spray. Dissolve one-cup iron sulfate (copperas) in a 5-gallon bucket and then spray the liquid with a backpack sprayer. Iron sulfate is not very soluble so all of the material may not dissolve. Just apply the residue to a holly, fruit tree, redbud, photinia, nandina, or one of the other plants showing iron chlorosis. The iron chelate products such as Sprint 138, Ferrimac, and Ferriplus are even more effective as foliar sprays than copperas but are also more expensive. Follow the label instructions.
April is the month to plant begonias, hardy petunias, lantanas, zinnias, and other color plants for summer blooms. Use the semperfloren begonias in the shade. They can also be used in the sun if they are planted now. Once the heat starts they quite growing, but with an early start they look good through the summer even in the sun. The new old-fashioned petunias like Laura Bush and Kahuna are very heat tolerant. They will make a good display all summer on a site that is enriched with compost, watered regularly, and mulched.
April is usually the month that peaches and plums are thinned of excess fruit. With the freezes, however, I would be reluctant to remove any fruit. Some fruit that begins development will abort within a few weeks due to freeze damage.
It will be clear by the second half of the month which shrubs, perennials, and container plants were damaged by the cold. Some bougainvillea, mandevillea, plumeria, and hibiscus will be killed and must be replaced. Other plants such as oleanders, Mexican heather, and citrus will have considerable top damage. Prune off the wood above the area where new sprouts are emerging.
In the vegetable garden plant your tomato, pepper, and eggplant transplants. It is also time to seed melons, gourds, green beans, and okra.
Dont forget the birds. The hummingbirds will be looking for the sugar water feeders. Use four parts water with one part sugar by the volume. The American goldfinches will stick around for most of the month. They are developing their breeding plumage, so keep their thistle feeders full so you can enjoy the color.
Songbird breeding season is upon us. The cardinals will be trying to fight their own reflections in the window and the woodpeckers may decide to use your rain gutters to tap their challenges to other males. Ignore them, the aggressive behavior will end after a few weeks.