Gardening This Weekend: March 16, 2023

When I looked at my 20 benchmark weather stations across Texas earlier today it looked like the northern half of the state either is facing a freeze or could be hit with a killing frost tonight and into the weekend. (Remember that frost can form on clear, still nights at 38F.)

With that in mind, here are things you can do to move yourself through this current cold and into the spring.

(This is information I leave archived on my website for dealing with late freezes.)

Question: What do I do when there’s a chance of late frost or freeze in spring?
Answer: For a late frost: Buds, flowers and tender new foliage are vulnerable to frost, which can form on cold, still nights, particularly if it is clear. Lightweight nursery fabrics will protect against frost damage and can easily be removed and stored for the next event. Secure them against winds that may accompany cold fronts.
For a late freeze: Floating lightweight nursery fabrics can still gain you several degrees’ worth of protection, provided they’re draped over your plants prior to the low temperatures, and if they’re left there until temperatures are back into the high 30s.
Some folks want to put a sprinkler under their fruit trees if a late freeze catches them in flower. That’s something commercial growers do, but they have specialized equipment and a great deal of training. You would have to be careful that the weight of the ice that forms doesn’t break the branches, and you have to leave the sprinkler running until the temperature has risen above freezing. Home gardeners are usually not encouraged to try this.
That all said, here are the “normal” things you’d want to do at this time of year. Wait a few days if needed and you should be just fine.

PLANT
• Warm-season vegetables including small and mid-sized tomatoes, particularly in southern half of the state. It’s still a bit risky farther north. Large-fruiting types do not set well in Texas conditions and should not be planted in any great numbers. Peppers, bush beans, crookneck and zucchini squash, cucumbers, and, for large gardens, melons and corn. Wait to plant okra until it turns warmer in mid- or late April.
• Warm-season annuals including marigolds, zinnias, cosmos, geraniums, coleus and wax begonias. Wait for warmer soils to plant vincas, lantanas, caladiums, elephant ears, moss rose and copper plants.
• St. Augustine or bermuda sod, but wait to seed bermuda until mid- April in South Texas and late April or May farther north.
• Trees and shrubs. Nurseries have their best supplies arriving now. New shipments come in Thursdays and Fridays each week. Protect tender new foliage from highway winds as you transport your new plants home.

PRUNE
• Trim to remove any shrubs’ branches that were obviously killed by that Christmas cold spell.
• Scalp lawn to remove winter, early spring weeds and to expose lawn to sun’s warming rays. Wear protective goggles and respirator. It’s a dirty, nasty job.
• Spring-flowering shrubs and vines as needed to correct errant growth. Trim as they finish blooming. Avoid shearing into formal shapes.

FERTILIZE
• Lawns in South and Central Texas as it warms up next week with high-nitrogen or all-nitrogen plant food. Aim for 30 to 40 percent of that nitrogen to be in slow-release form. Wait until last week of March or early April to fertilize lawns in North Central and North Texas.
• Unless a recent soil test shows otherwise, that same high-N or all-N fertilizer will be best for landscape plants and even flowers and vegetables.
• Newly transplanted flowers and vegetables and newly repotted patio plants with diluted solution of water-soluble or liquid plant food (high-nitrogen) with each watering for the first month.

ON THE LOOKOUT
• Chickweed, dandelions, clover, dichondra and dollarweed can be controlled with application of broadleafed weedkiller (containing 2,4-D) once weather warms up in a few days. Read and follow label directions carefully for best results. Be patient – these products may take a week or two to show maximum results, and you may have to treat more than one time for tenacious weeds. Small droplets that coat the weeds’ leaves are most effective.
• Aphids congregate on tender new growth of many types of plants. Colors will vary from green to red, black, yellow or orange, but all will have pear-shaped bodies and twin “exhaust pipes” on either side. They are easily controlled with almost any organic or inorganic insecticide. You may even be able to wash them off with a hard stream of water.