Winter Anti-transipirants

Protect Your Broad-leaved Evergreens from Dessicating Winter Winds

Jan 10, 2008

Northern winters tend to ravage unprotected broad-leaved evergreens, causing unsightly damage, often called "winter burn." Anti-transipirants can prevent such damage.

As northern gardeners emerge from winter's cocoon each year, the task of assessing the landscape quickly turns to damage control. Boxwoods (Buxus), Rhododendron, hollies (Ilex) and mountain laurels (Kalmia) appear dilapidated, and sometimes completely dead. Typically, the reason for this is simple. Frigid winter winds literally dry the leaves out. Fortunately, there is a two-fold solution to this common landscape ailment.

Commonly referred to as "winter burn," the browning of leaves is caused by harsh winds combined with one of a plant’s normal homeostatic processes called transpiration. The leaf utilizes this process in summer to cool the plant down. Moisture is released through pores in the leaf tissue, called stomata. The evaporation of the moisture into the air cools the plant. Wind accelerates this process. In the winter, the ground is frozen, so a plant cannot absorb water to replace what is lost. The desiccation manifests as brown blotches and withered or curled leaves. The leaves often fall off completely.

Any evergreen in the landscape is potentially vulnerable to winter wind, particularly if temperatures are abnormally cold for prolonged lengths of time. But broad-leaved evergreens are considerably more susceptible than their needled counterparts. This is mainly due to the surface area of the leaf. Small-needled evergreens such as hemlock (Tsuga) or spruce (Picea) are far less likely to suffer from winter desiccation, as the surface area of their leaves is quite small.

Anti-transpirants are designed to literally seal the leaf stomata to prevent water loss. These products are sprayed onto the plants’ foliage beginning in early winter. The sprays contain varying polymers that eventually wear away in normal weather conditions. They should be re-applied at intervals listed on the product’s label. One important consideration with anti-transpirant sprays is timing. Since sealing the stomata of plants prevents transpiration, application should not occur in warm weather. Fall and spring temperatures are often warm enough to illicit normal plant transpiration. If the stomata are sealed, the plant could suffer.

Of course, spraying anti-transpirants alone might not always be effective. Winds are more prevalent depending on exposure. Placing boxwood in the middle of a windy backyard is a recipe for disaster. Even rigorous application of an anti-transpirant product will not protect the plant from winter damage. The placement of any planting in the landscape is crucial to success. Broad-leaved evergreens should always be planted in protected locations. Limiting the source of transpiration (wind) is the best way to prevent winter desiccation. Use anti-transpirant sprays as a supplement.

The copyright of the article Winter Anti-transipirants in Landscaping is owned by Jesse William DiBona. Permission to republish Winter Anti-transipirants in print or online must be granted by the author in writing.