Heat and Drought Tips and Tidbits for the Garden

From M & M Landscape and Lawn, Inc.'s July, 2006 Newsletter

As if gardening chores aren't strenuous enough by this time of year, Mother Nature's heat wave is making life even more difficult. It seems as if a mid-summer drought is a fact of life in the Southeast. In recent years drought periods have ventured into spring and fall. There are a few things you can do to ease your plants discomfort and ensure their livability during these periods of heat and drought.

Newly set transplants will require more frequent watering and will benefit by shading from midday sun to avoid wilting. In some cases, plants will wilt during midday despite all your effors simply because the leaves are losing moisture faster than the root system can take up water. In this case, the plants should recover in the evening and morning hours when temperatures are cooler.

Container plants on the patio will be streesed by the heat wave since they have much less buffering of temperature extremes on the root system. In addition to watering more frequently in hot weather, provide afternoon shade, if possible, to help keep them a bit cooler. Also, consider planting your container plants in some of the newer lightweight foam planters that are available. The thickness of the form containers will provide some insulation between the plant's roots and the heat of their environment. Be sure to drill drainage holes in the container if none are present.

HGTV personality and Master gardener Paul James fields view questions about hot-weather gardening:

Q. What does drought-tolerant really mean?

A. The term drought-tolerant is used to describe plants that will grow well with little, if any, supplemental water. However, what is often lacking in that description is one key phrase, namely, "once established". I'm not aware of a single landscape plant that you can simply stick in the ground and expect to grow without water, especially during that first critical year.

It's during the first critical year of growth that plants become established, meaning they develop a healthy root system and become acclimated to the soil, the weather, basically the whole environment. Some plants take longer than others to become established. So make sure you water new plantings routinely, as often as everday or as little as once a week, depending on the type of plant and it's requirements, until it seems capable of supporting itself with only the occasional watering or from rainfall alone.

Q. During the heat of summer, isn't it better to water landscape plants every day?

A. Watering daily during the summer is absolutely not a good idea, because even in the middle of summer, you can overwater plants. Even if you water lightly, the water won't penetrate very far which means roots will hover near the surfact of the soil. It's important to water once or twice a week in a manner that it percolates deep within the subsoil. By deep-soaking, you encourage roots to likewise venture deeper into the subsoil in search of water. And as a result, those plants are far better equipped to handle drought conditions.

Q. How can plants make the environment cooler?

A. Plants make the environment coller, thanks to a process called evapotranspiration. Take an oak tree, for instance. As it secretes, or transpires, moisture through it's leaves, this water draws heat as it evaporates, thus cooling the air in the process. Incredibly, a large oak tree can easily release up to 40 gallons of water in a single day. When combined with the shade it casts, trees can make a huge difference in energy costs when planted on the south and west sides of a house.

Q. What are some of the most heat-tolerant perennials?

A. Thankfully there are lots of them, and the following plants are a few of my favorites that are readily available, establish theselves quickly and grow magnificently throughout much of the country. Topping the list are the ornamental grasses. Once established, ornamental grasses are among the most drought-tolerant and carefree plants on the planet. Once more, they're beautiful in almost any setting throughout much of the year. Daylilies are another sure thing. Because they bloom for months you get a lot of bang for your buck. Despite it's dainty appearance, coreopsis is tough as nails and can really take the heat. The same can be said for coneflower (Echinacea) and black-eyed Susan (Rudbeckia). In fact, you could create a terrifc drought-tolerant garden with just those five plants. Of course, you could also add iris and a number of evergreens, such as junipers, spruces, and pines. Finally, there are the obvious choices, cacti and succulents which make outstanding additions to the landscape or look great in containers, too.

One last thought on heat and drought tolerance in plants. If you haven't already done so, mulch, mulch, mulch. Mulch is invaluable around the root zone of your plants to help hold in what moisture is avilable to the plants to help them through the heat and drought.

Try not to overdo the garden work in the heat, over-exerting yourself in extreme hot weather can be very dangerous to your health. Aim to complete your chores very early in the morning, take frequent breaks, and drink plenty of water to keep yourself from wilting.