April Gardening Guidelines
by Keith C. Hansen, Extension Horticulturist, Smith Co. – Tyler, Texas
April brings spring gardening is to a fever pitch, and nurseries are fully stocked with all kinds of plants and products for every purpose for the itchy green thumb. Here are a few gardening tasks for the month of April that you might find helpful.
April is an ideal time to evaluate your azalea beds and think about adding a group of azaleas which bloom later than the main “Tyler Azalea Trail” blooming season. There are many varieties which begin to bloom after the main Trail types – Southern Indicas and Kurume, have faded, with some types even waiting until late April and May to bloom. Visit your local nursery to see the many varieties of azaleas available.
A common azalea question is: “When do I prune my azaleas”. Since they bloom on growth produced the previous year, you must wait until they finish blooming before pruning. The same holds true with spirea, forsythia, pearlbush, wisteria and any other early spring blooming plant. Azaleas don’t have to be pruned every year, but you might find it desirable to remove long shoots sticking up above the rest of the bush to keep the growth more compact.
Climbing roses may also be pruned as soon as they complete flowering.
Camellias should be fertilized this month, and once azaleas finish blooming, fertilize them, too, to stimulate new growth. Just be careful not to fertilize too heavily, and evenly distribute the fertilizer over the root zone. Their shallow roots can be easily burned when fertilizer is applied in concentrated piles.
Roses have relatively high fertility requirements, so fertilization can begin now and continue every 4 to 6 weeks until September.
April is the month to begin fertilizing lawns. The ideal time to apply fertilizer is after you have mowed actively growing grass once or twice. Early April is a good target date for St. Augustine and common Bermuda grass. Centipede lawns are usually slower to green up and turf experts recommend that they be fertilized in early May. For best results, have your soil tested for pH and fertility before applying fertilizer. Soil test kits are available from all county Extension offices; otherwise use a 3-1-2 or 4-1-2 fertilizer ratio.
Annual flowers may be seeded now, including amaranthus, celosia, cosmos, marigold, portulaca, zinnia, gomphrena, and several other warm-season annual flowers. These can be sown directly in the beds where they are to grow. Keep seeded areas moist until seeds germinate. Thin out as soon as they are large enough to transplant so the remaining plants will not be crowded. Surplus plants can be transplanted to other areas.
For faster color, purchase annuals already started. Select short, compact plants, preferably ones that have not yet begun to flower. Remove flowers and buds to give the plants an opportunity to become well established before flowering.
One of the best hot-weather, summer plants is the periwinkle (vinca). Eager gardeners setting out vinca too early may lose it to a fungal blight. By waiting until it gets hot (later in May) to plant vinca in the sunny part of the yard, you almost totally avoid this problem. Mulching can also help reduce disease problems by reducing soil splashing up onto the leaves.
Perennials for summer color include lantana, daylilies, verbena, hostas, salvia, sedums, ornamental grasses, purple coneflower, rudbeckia, ferns and summer phlox.
There’s still time in early April to plant many vegetables, including bush and pole beans, cucumber, cantaloupe, sweet potatoes, pumpkin, summer & winter squash, and watermelons from seed; and transplants of tomatoes, peppers and eggplants. All these should be seeded or transplanted right away for best results. Okra and Southern peas do better with warmer soil and therefore should be planted a bit later in the month.
I often see garden plots with very crowded rows of vegetable seedlings. Without thinning these seedlings to allow room between each individual plant, the plants will be weak and spindley and the harvest will be disappointing.
Follow recommended spacing distances between plants for each crop. For example, green beans should be thinned to a 3 – 4 inch spacing, while lima beans grow larger and need 4 – 6 inches. Pole beans need about 6 inches between plants. If the plantlets are very large, and pulling would disturb their neighbors, thin by clipping the shoots off at ground level. Greens, like lettuce, collard and mustards, should be thinned several times until you get the final spacing. That way you can eat the “thinnings”.
Store left over vegetable seeds in a sealed container in the refrigerator if you’d like to keep them for next season. A tablespoon of powdered milk wrapped in tissue can help absorb moisture to keep the seeds fresh.
For best growth and yield, make additions of nitrogen fertilizer (called side dressing) every couple of weeks, starting about a month after transplanting or seeding. This will keep vegetables growing vigorously so they reach their maximum yield potential.
Watch new growth for insect pests. Aphids, also sometimes called plant lice, may get on the new growth of any type of plant. While a few aphids can be tolerated, large numbers can distort growth and should be controlled. A strong jet of water to knock them off can provide temporary control, and insecticidal soap products will also help control them.
Check the East Texas Gardening Program Calendar for upcoming gardening events in Smith County and the area.