By this point on the calendar, we're pretty committed to spring. Temperatures are climbing, and plants are in their growth spurts. It's a fun time in horticulture, but there also are tasks to be tackled. Here are some of the most critical.
The next several weeks will be your best time for planting new turf grass. Soils are warm enough that grass roots will establish quickly, yet temperatures are still cool enough that watering will be less challenging. So, if last summer's drought left you with gaps in your grasses, this is your time.
Perennials are widely available in area nurseries right now. Prepare your bed carefully, and choose your types wisely. Have a color scheme, and know each plant's bloom cycle, so that several types will be in flower at any given time through the season. Leave space to plant types that won't be available until fall.
Tropical annuals are making appearances in nurseries now. Hibiscus, bougainvilleas, mandevillas, crotons, firebush, Gold Star esperanza, brugmansia (angel's trumpet), copper plants and cupheas are all arriving. Soils are also finally warm enough to start planting caladiums and elephant ears. Conventional hot-weather annuals, including lantanas, pentas, fanflower, gomphrenas, fountaingrass, moss rose and hybrid purslane, can also be planted now. Wait, however, until June to plant vincas, once the danger of hard, splashing rains and the water mold funguses they encourage have abated.
Trees, shrubs, vines and ground covers fill every nursery here in the heart of springtime. However, supplies will shrink as May turns into June, so do your shopping immediately. They'll establish well, as long as you keep them watered regularly from now into the fall. New plants will dry out more rapidly than the surrounding soils, so sprinkler irrigation alone will not be sufficient.
Mow at the recommended height for the type of grass that you're growing. Common Bermuda should be cut at 11/4 to 11/2 inches. Hybrid types' mowing heights will vary with the variety. Zoysia's proper mowing heights will also depend on the variety. St. Augustine should be maintained at 2 to 21/2 inches. Keeping grass at its recommended height will encourage dense turf that resists invasion by weeds. Tall grass quickly becomes weak grass.
Reshape your spring-flowering shrubs and vines now that they've finished blooming. Remove weak and spindly growth that probably won't bloom again. Avoid formal shearing into unnatural shapes, but take this chance to remove erratic growth that extends far beyond the plants' foliar canopies. Abelias, Lady Banksia roses and elaeagnus all produce rampant shoots that should be removed with lopping or hand shears. Trim them back into the plants' canopies so the cuts won't be so visible.
If you have overgrown houseplants, this is your chance to repot and reshape them. Trim them back farther than the minimum to allow room for attractive regrowth. Apply a water-soluble, high-nitrogen plant food with each watering.
By now, almost all of your plants are growing actively. With this spring's rains, they'll need a renewed supply of nutrients. Soil tests show that almost all of our Blackland Prairie soils are excessively high in phosphorus (the middle number of the fertilizer analysis), yet low in nitrogen (the first number). That's why you'll see the recommendation to apply an all-nitrogen fertilizer to plants ranging from turf grass to tomatoes, fruit trees to ferns. The fertilizer should have half or more of its nitrogen in quality, slow-release form.
If you have plants that are showing iron chlorosis, this is the proper time to start treating. If you're seeing yellowed leaves with dark green veins, and if they're more prevalent at the ends of the branches, those are the classic symptoms of iron deficiency. Apply an iron amendment that also includes sulfur. The plants don't actually need the sulfur -- they need what it does to lower the pH and keep the iron in a soluble form. Note: Keep all iron products off masonry and painted surfaces, to avoid rust-colored stains.
Deal with pests
Bagworms were terrible last year, and they could be again in 2012. Start watching your junipers, arborvitae and cypress plants early in May, and check them several times weekly into mid-June. The larvae start out very tiny, but you'll be able to see them pulling their tiny bags around behind them as they feed. At that point, Sevin, Bacillus thuringiensis biological worm control or other labeled product will easily eliminate them before they do serious damage.
Watch, too, for early-season webworms in pecans, persimmons and other host trees. Trim the webs out with a long-handled pole pruner at first sighting. Sprays are difficult and not very effective in penetrating into the webs to kill the larvae.
If you have broadleafed weeds such as dandelions, clover, dichondra or dollarweed in your turf, apply a labeled herbicide that contains 2,4-D. Most will also contain two other active ingredients, and they do require care in applying them near trees and shrubs. Properly applied, they'll eliminate all the nongrassy weeds over a 10-day period. Dallisgrass, by comparison, must be spot-treated with a glyphosate herbicide applied directly to the clumps. The weed killer will also kill surrounding turf, so be as precise as you can in applying it. There is no selective herbicide that will kill dallisgrass, or any other weedy grass, without harming the lawn.
Finally, if you have nutsedge invading your lawn and landscape, try the original Image or SedgeHammer herbicides. They don't work quickly, but they're reasonably effective -- more so than any other product available. Read and follow label directions.
Neil Sperry publishes Gardens magazine and hosts Texas Gardening 8-11 a.m. Sundays on WBAP AM/FM. Reach him during those hours at 800-288-9227 or 214-787-1820.