Drought in the Landscape

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The Caldwell Extension Center has received numerous calls the last few weeks about evergreen trees.

drought stricken evergreens

These arborvitae are suffering from drought stress. The brown leaves are due to lack of water, not a disease. (Photo Credit – Elina Snyder)

Upon investigation, the trees have yellowing needles from drought stress. Caldwell County has received only 3.8 inches of rain since the middle of August and we are over 10 inches below normal rainfall levels for the year. The North Carolina Drought Management Advisory Council (http://www.ncdrought.org/) classifies Caldwell County as moderate drought conditions.

Droughts and dry conditions are just part of life. To quote our NC Commissioner of Agriculture, “It is always too dry, too wet, to cold or too hot”. We can’t change the weather, but we can have a plan to help until conditions improve.

Perennials are plants or trees that live for more than two years, and many of our landscape plants are perennials. Younger perennial plants (in the ground for 2 years or less) are the most susceptible to drought stress. Their roots are not as well-established as their mature counterparts. However, older perennials still experience stress and one drought year can have health effects in subsequent years. Plants to prioritize watering this fall are:

  • Young perennials and trees.
  • High-value plants, important plants in the landscape such as shade trees, or plants with sentimental value.
  • Plants that would be difficult to replace, such as rare species.
  • Because evergreens keep leaves and needles throughout winter, moisture continues to be pulled through the plant throughout the winter. It is important to keep moisture available to the plant throughout winter. They should receive 1” per week.
  • Drought-sensitive perennials such as hydrangeas, Japanese maples, azaleas, and dogwoods.
  • Consider watering your lawn or garden this fall to reduce the long-term stress that plants experience.

If you are establishing a tall fescue lawn, set up a temporary irrigation system. Also use a light layer of straw as mulch over the grass seed to help conserve moisture. The same technique can be used for cover crops seeds that are sowed in the garden. Cover crops help improve the soil.

Plants lower on the priority for watering include fading summer annuals, plants that are chronically stressed and perform poorly, and plants in crowded beds. There is no need to waste time and resources on these plants.

Watering is the short term solution for plants suffering from current dry conditions. However there are long-term strategies to help gardens and landscapes so future dry conditions will be less devastating:

  • Choose drought-tolerant plants for areas that stay dry or that are difficult to irrigate.
  • Incorporate compost (organic matter) into the soil to improve the water holding capacity. Every 1 percent of soil organic matter holds an additional 16,500 gallons of plant-available water per acre.
  • Consider connecting roof downspouts to landscape beds.
  • Consider installing an irrigation system or soaker hoses to supplement rainfall during dry conditions or when establishing seedlings or transplants. Most plants thrive with approximately 1” water per week. Put a rain gauge in your garden or landscape to measure rainfall. Use this information to know how much supplemental irrigation is needed.
  • Mulch to conserve moisture. Mulches typically conserve water and can cool the soil during hotter periods. Straw is one good choice for mulch in the garden or when sowing grass. Use 2 to 4 inches in the garden around transplants. It will conserve moisture and suppress weeds. When sowing grass, apply enough straw to the surface where you can still see some soil. If the straw is too thick will prevent the grass seed from establishing and make mowing difficult. In the landscape wood mulch is better choice. Apply to 2 to 3 inches of wood mulch in landscape beds.

This news article was adapted from “Dealing with Drought” by  Lucy Bradley- NC State Urban Horticulture Professor and Extension Specialist. The factsheet is available online at (http://go.ncsu.edu/coping-with-drought) or by contacting the Caldwell Extension Center. For specific questions about your garden or landscape contact the Caldwell Extension Center at 828-757-1290 or visit us anytime online at //caldwell.ces.ncsu.edu.