March is a major gardening month in the San Antonio area. The weather stabilizes and by the end of the month it is warm enough to consider planting warm season plants. The last average freeze date occurs during mid-month
Birds and Wildlife
- Later this month, we may see the first hummingbirds. They will seek out the cross vine, columbines, salvia and honeysuckle. This can be one of the best months at your feeders if you put them up this month. Black chin, ruby-throats and rufous hummingbirds will show up sometime during the month.
- Thistle or hulled sunflower seeds attract the goldfinch flocks that linger until May. Seeds are still scarce this month. Cardinals and purple finches are active and the doves show up at the feeder.
- Purple martins will be settling in this month. Be sure your houses are cleaned, raised, and placed at least 25 feet away from trees to allow a clear flight path to the house.
Color
- You can cut tulip foliage down as soon as it is unattractive because they won’t come back anyway. On daffodils, Dutch iris and other low-chill bulbs, however, leave the foliage until it turns brown. The green leaves are replenishing the bulbs for next year’s blooms.
- Fall-planted pansies, snapdragons, dianthus, stocks, alyssum and larkspur are spectacular this month.
- Containerized plants can still be put in the landscape this month.
- It is not too late to plant daylilies and irises if they are well rooted in containers.
- March is great geranium month. Use them in morning sun locations.
- If the weather is warm after the 15th, consider moving the bougainvillea, plumeria, and hibiscus on to the patio.
- Wildflowers will begin blooming this month. Remember, they must be allowed to mature their seeds if you want new plants next year; that means they’re going to be brown and ugly before the seeds are mature.
- Plant hibiscus, bougainvillea, mandevilla and allemanda vines in containers for tropical landscape color.
- Impatiens, fibrous begonias and coleus are summertime favorites for shade. In areas where space is limited, plant your favorite flowers and vegetables in containers or hanging baskets.
- Perennials which can be planted now include perennial phlox such as ‘John Fanick’ and ‘Victoria’, iris and daylilies.
- Be on the lookout for a spectacular spring wildflower display. The spring months in South central Texas are perhaps best known for their Indian paintbrush, mountain laurel, winecup, pink evening primrose, prairie verbena, horsemint and, of course, the bluebonnets.
Fruits and Nuts
- You can spray fungicides while the trees are in bloom, but not insecticides. The bees are still pollinating your fruit trees and are susceptible to the sprays.
- Do not fertilize fruit trees after they start bearing fruit. Too much nitrogen will cause the fruit to abort.
- It is not too late to spray dormant oil on the trunks of pecans to control phylloxera. Also apply one cup of slow release lawn fertilizer per inch of trunk diameter. Spread thinly throughout the drip line so as not to burn the grass and use a chelated zinc product such as Pecan King.
- When peaches are the size of a dime, thin them to one fruit every 6-8 inches of stem. If you don’t thin, you will have a tree full of small fruit and broken branches.
- You can still plant the thornless Navajo blackberry. The fruit is as large as Brazos and Roseborough, is sweeter and ripens in late June and early July, Keep in mind that late fruits need irrigation to produce large fruit.
Ornamentals
- The bluebonnets should begin flowering this month after a major growth of the foliage. Do not over-water them as they are xeriscape-type plants.
- Cross vines put on a spectacular show this month, but “Texas Gold” columbines are even more impressive, especially when fertilized frequently. If you buy one, be sure it says “Texas Gold” on the tag in the pot.
- Keep up the spray regimen with roses.. .Orthene and Funginex are the favorites. Fertilize with rose food every 4-8 weeks according to the label instructions. Select old-fashioned rose varieties if you want plants that are easy to care for.. .they grow well in our soils.
- Use a pre-plant application of a slow-release fertilizer analysis such as 19-5- 9 at the rate of 2-3 pounds per 100 square feet of garden planting area. Early March is the ideal time to fertilize landscape plants because you give them food just before the spring growing season starts.
- March also is a good time to divide and transplant mums, ajuga, liriope, daylily and Shasta daisy. Repot overgrown, root-bound pot plants. Keep plants in light shade until re-established.
Shade Trees And Shrubs
- Be careful not to get lawn herbicides too close to trees. Weed-and-feed type fertilizers are notorious for killing young shade trees.
- If you plant container-grown trees this month, be sure to make an 8 ft. circle around the tree for mulch which will keep the grass at bay. Do not add organic material to the planting hole. The tree needs to root in the soil in which it will live the rest of its life.
- Paint all wounds on oak trees immediately to prevent oak wilt.
- Ball moss is not a parasite on oak trees, but if you don’t like the looks of it, spray copper hydroxide (Kocide) or a 3 percent solution of agricultural baking soda this month.
- If you see army worms or leaf rollers on your oak trees, apply Bt, Spinosad, or Malathion quickly once they appear.
- Fertilize trees early this month if you missed it last month. Use one lb. (2 cups) slow-release lawn fertilizer per inch of diameter spread throughout the drip line or place in aeration holes.
- Finish any pruning except for the early bloomers such as climbing roses, mountain laurel and ornamental fruits. Prune them after they lose the major flush of blooms.
- Check mountain laurels for worms. Use Bt or Spinosad to control them.
Turf Grass
- It’s still too early to fertilize the lawn. It may begin to green up, but the root systems are not fully active until warmer weather arrives. Any greening that occurs this month is due to fall fertilization. Do not use “weed-and-feed” type products. They only encourage weeds to grow more vigorously. Wait until at least next month to fertilize.
- March is a good month for aeration and adding a half-inch of compost as a soil dressing if you haven’t done so in two years.
- Apply pre-emergent broad-leaf herbicides like Amaze, Balan or Betasan if you didn’t apply them last month. Read the labels carefully and be sure your weeds are listed. The weeds that are already up may be killed by the coming heat or with contact herbicides like MSMA or glyphosate. Follow instructions on the label carefully.
- Mow your Asiatic jasmine at the highest level on your mower to encourage a new growth of leaves. This is a good month to plant ground covers.
- It’s too early to seed a Bermuda lawn; seed will not germinate until late April or early May.
- Tune up the lawnmower and be sure the blade is very sharp. Remember that dull blades tear the grass, sharp ones cut it.
- Check out the automatic lawn sprinkler system for leaks, broken pipes or heads, or wasteful misting.
- In heavily shaded parts of the landscape where grass is difficult to maintain, choose one of the well-adapted groundcover plants such as English or Algerian ivy, Asian jasmine, or mondograss.
- Establish or renovate the lawn as needed. Re-sod or replant with turf grasses adapted to this part of Texas and suited to the planting location (shade or sun).
Vegetables
- Put the containerized tomatoes in the ground towards the end of the month. Save some for April planting and a few for May in case of weather problems.
- Don’t forget to keep onions and cole crops well fertilized with one cup of slow-release lawn fertilizer per 10 feet of row this month. Thin out the onions to 6 inches apart. Use the thinned ones for green onions.
- March is a month to plant the gardener’s favorite vegetables such as tomatoes, sweet corn, snap beans and peppers as well as cucumbers, lima or butter beans, cantaloupe, okra (if the soil has warmed sufficiently–70 degrees F. or higher), southem peas, pumpkin, squash, peanuts and watermelon.
- The last frost of spring may have already occurred but even if it doesn’t frost the wind WILL blow. Protect tender transplants and seedlings with Grow-Web (Plant Guard, ReeMay, Plant Shield) for wind protection, insect avoidance and unexpected cold (3-5 degrees cold protection).
