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Water Your Landscape Plants

The rapid onset of unhealthy-looking landscape plants is cause for concern. Many landscape plants in Illinois are suffering from extremely dry weather. Symptoms include severe leaf wilt, yellow leaves, early fall coloring, and leaf scorch (browning along the margins) on broadleaf plants, and brown, dying turfgrass.

The symptoms are a result of the roots failing to supply sufficient water to the leaves. This inability is influenced by the moisture content of the soil and by the location and condition of the root system. The drought conditions have significantly reduced some plant root systems, making them unable to supply enough water to compensate for the tremendous amount lost through the leaves.

As would be expected, some plants are affected more by drought conditions than others. Especially affected are potentilla, hydrangea, viburnum, euonymus, and holly shrubs; redbud trees; spruce and hemlock conifers; and bog plants such as iris and astilbe. Fortunately, our native prairie species adapt well to these conditions and, although the top growth is dying back, this dieback helps build reserves into the crown for growth next season.

Knowledge of plants' normal growth habits is important. For example, although many white pines continue to show signs of stress (see "White Pine Problem" in issue No. 12 of this newsletter), these pines naturally drop last year's needles in late August through mid-October. By contrast, most other pines and spruces keep several years of needles. If they begin to drop last year's needles, severe stress or disease could be present.

To save the landscape plants, water any stressed plants now to encourage recovery growth and root revival. Apply enough water to penetrate deeply within the dripline. Newly installed plants, especially those in containers, should be watched carefully and watered properly. Never overwater. To prevent plants from sending out succulent, frost-susceptible growth, avoid fertilizing or pruning until plants are dropping their fall leaves.

Author: Floyd Giles Rhonda Ferree


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