Garden Checklist for March 2013

Dr. William C. Welch, Professor & Landscape Horticulturist
Texas A&M AgriLife Extension
  • Often, tomato and pepper plants started outdoors from seed will grow so quickly they will catch up with commercial plants in size within a few weeks. For many gardeners, this is the only way to obtain rare or heirloom varieties. But because this has been a winter with erratic weather patterns, it's best to keep an eye on young tomato transplants so that they may be covered if the threat of a late frost occurs.
  • Don't be in a hurry to set out young pepper plants. Wait until the temperatures seem to be settled.
  • Pruning of evergreens and summer flowering trees and shrubs should be completed in early March. Prune spring flowering trees and shrubs as soon as they finish blooming.
  • Start hanging baskets of petunias, ferns and others for another dimension in landscape color. One attractive begonia plant can yield a number of others through careful rooting of stem cuttings.
  • Plant dahlia tubers in fertile, well-drained soil.
  • In North Texas there is still time to plant seeds of your favorite annuals in flats to be transplanted out-of-doors when danger of frost is past.
  • blue plumbago
    Blue Plumbago in a San Antonio landscape
  • Select and order caladium tubers as well as coleus plants for late April and early May planting. Do not plant caladiums until soil temperature reaches 70°F.
  • As camellia and azalea plants finish blooming, fertilize them with three pounds of azalea-camellia fertilizer per 100 square feet of bed area. Check mulch on azalea and camellia beds and add where needed.
  • Fertilize roses every 4 to 6 weeks from now until September.
  • Beware of close-out sales on bare-root trees and shrubs. The chance of survival is rather low on bare-root plants this late in the season. Your best bet at this time of year is to depend on container-grown or balled-and-burlapped plants for landscape use.
  • Plant Blue Plumbago (Plumbago capensis) now for season long low maintenance color. It is usually cold hardy to Zone 8 and sheltered places elsewhere. Although tolerant of sunny conditions, blue plumbago prefers a little protection from the hot afternoon sun. It is quite drought tolerant and blooms from spring till frost.
  • Now is a time to thin larkspur, zinnia, cockscomb and cosmos seedlings. Plants will bloom much better if thinned to about 4" apart. Transplant or share the extras with gardening friends.

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