Saving your plants from dying in the heat

Sunday, July 22, 2012
Kelsi Siebert shows the fertilizers that can be applied in the fall to help lawn and landscape recover from heat and drought stress. (Fred Lynch)

Last year we were flooded in the spring. This year spring came early. Then Mother Nature turned off the rain spigot and turned on the summer furnace. During all of this the population of voracious Japanese beetles continued to increase and devour roots, flowers and leaves. What's a plant to do?

Plants are kind of like people. When you or I are exposed to stress for a long period of time, we become susceptible to minor ailments that normally would not bother us. But because we are weakened by the stress, that minor ailment may become a major issue.

With this idea in mind, the best thing that we can do for the perennial plants in our lawn, landscape or garden is to apply cultural treatments that will encourage them to grow rapidly this fall and next spring in order to put them on the road to a healthy recovery. Below are suggested remedial practices you can perform for different areas of you landscape.

* If you have a zoysia or Bermuda grass lawn, make sure that you fertilize it this summer with a fertilizer such as a 24-0-4. These warm-season grasses can use an extra boost of nutrients in order to get growing rapidly yet this summer and before they begin to go dormant this fall.

* Evaluate a lawn consisting primarily of cool-season grasses such as fescue, rye or bluegrass in late August. If there are not a lot of bare areas, schedule an application of a high-nitrogen fertilizer such as a 24-0-4 early in September. Then return in about six weeks and apply a winterizer fertilizer such as a 25-0-5. These applications will give your lawn the needed nutrition to make your lawn grow rapidly and repair most of the damage resulting from the extreme conditions of this summer.

* If a cool-season lawn has a lot of bare spots, plan on reseeding early in September. Make sure that you apply a new lawn starter such as a 9-13-11 at that time. Then in about four weeks apply a 24-0-4. Wait another six weeks and apply the 25-0-5 mentioned above. Next spring your lawn should look great.

* Apply 11-15-11 with micronutrients to any herbaceous perennials such as day lilies, astilbe, salvia, etc. in your landscape in late August or early September. This unbalanced combination of nutrients will encourage your perennials to spend their energy on developing a good root system this fall in order to be strong and healthy next spring.

* In late August or early September you should also apply a fertilizer similar to the 11-15-11 for your broadleaf evergreens such as azaleas, nandinas, boxwoods and abelias. I would also make the same fertilizer application for evergreens such as pines and arborvitaes, as well as for deciduous shrubs and trees such as oaks, burning bush, and forsythia and roses.

You will notice that sometimes I mention a fertilizer with nitrogen higher than phosphorus (the first number is nitrogen and the second number is phosphorus), while at other times I mention a fertilizer with phosphorus higher than nitrogen. Nitrogen promotes leaf and shoot development, while phosphorus promotes root development.

These applications will start your landscape plants on the road of recovery this fall, but they will also need additional help next spring. At that time apply fertilizers again in order to continue the redevelopment of a good root system that will support foliage, flowers and fruit for your lawn and landscape plants.

Send your gardening and landscape questions to Paul Schnare at P.O. Box 699, Cape Girardeau, MO 63702-0699 or by email to

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