Plant Answers

Weekly Express-News Article
Saturday, February 4, 2006
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist

“Landscape Practices to Delay”

My colleague, Jerry Parsons, on our radio show “Gardening South Texas” makes fun of me when I recommend that gardeners wait as long as possible to prune back the freeze killed foliage on root hardy perennials and annuals. I recommend the delay because the killed but standing foliage provides food searching habitat for birds that feed at lower levels in foliage and on the ground. The stems may look empty of food, but on closer examination there are seeds and hiding insects. The standing plant material, even when it is brown and crispy, provides shelter from cold, winds and rain (if it ever rains again!). Cut back the dead areas when the availability of time and your aesthetic sense requires it, but the delay for the birds does not hurt the plant and may in fact reduce the amount of freeze kill from late freezes.

Another delay that is desirable, is that of fertilizing and watering your lawn. This delay will not help the birds, but it will save you money and reduce environmental stress. Our hot weather grasses – Bermuda, St. Augustine, buffalo, and zoysia do not start growing until the soil warms up (late April). Applying fertilizer between now and mid-April will result in the waste of much of the nitrogen in the fertilizer. The inactive grass can not pick up the nutrients from the fertilizer. The weeds that are growing activity will like it, but the grass will not benefit.

Water is a more complex issue because even when St. Augustine grass is dormant it requires some water every three – four weeks to maintain its health. Any more than that, however, and water is wasted. Water that you are paying for. The unnecessary water applied to the lawn also raises your year round sewer bill. Sewer bills are calculated based on winter water use because the theory is that all the water used in the winter is indoor water that goes into the sewer to be treated. The calculation is called “winter averaging.” The infamous Dr. Parsons is advocating that “winter averaging” is not fair in 2005 – 2006 because of the drought and the need to apply some water to St. Augustine grass. It is an interesting idea, but not likely that SAWS will change the calculation. The best thing to do is to be conservative in your outside water use.

Delay in cutting back your freeze killed plants, applying lawn fertilizer, and irrigating the lawn will benefit the environment and your water bill. There are some activities in the landscape, however, that should not be delayed.

Do not delay planting trees and shrubs. The prices are right at area nurseries and the quicker you can get them in the ground, the more time the plant has to develop roots before hot weather arrives. It is also recommended that the lawn should be aerated and top dressed now. Rent an aerator that cuts plugs from the lawn rather than pokes it with spikes. The plug cutter does not compact the surrounding soil as much as the spike. Aeration reduces compaction and lets water and nutrients penetrate more easily to the roots. Top dress with a half inch compost after the aeration and organic material will infiltrate to the root system. Aeration and top dressing are magic elixir for lawn health, do not delay doing it!