End of Spring care for
Junipers, Leylands and Hollies

Charlie Metz
Frederick County Master Gardener Program

As the end of spring approaches, Junipers, Leylands and Hollies aren't looking very good. What is going on?

We have had weather conditions at both ends of the spectrum. Our county had a serious drought condition in spring, summer and early fall of 2002. Long stretches of time without rain were only interrupted by short showers with little rain. This put most lawns into dormancy or death and stressed trees and shrubs. Municipalities responded by imposing mandatory water restrictions.

Trees and shrubs depend on regular water supplies to go through their life cycles. Leaf growth,' flowering and manufacturing food in the form of sugars are all dependent on adequate and regular water supplies. Many plants adapt to occasional lack of water by sending deep roots to tap into moist subsoil.

But many plants used in the landscape are not native to our area. Many are from parts of the world that seldom have serious drought and have smaller root systems. As long as we keep them watered, they usually do well. However, if the community says not to water, then we are restricted from supplying what the plants need.

Plants prepare for winter by slowly shutting down their systems in the fall. By then, next year's growth is contained inside buds. If these buds are formed under stress conditions, it is possible the upcoming winter could damage the plant.

However, rains returned in the middle fall of 2002, and most plants adapted. Except for a huge snowstorm in February 2003, the winter of 2002-2003 was normal. But the stage was set for stressed-out plants.

The spring of 2003 began with what seemed like rainfall every other day. Most of us were glad to see this rainfall since it had been so dry. We even didn't mind mowing the lawn every four days because we didn't have to mow much the year before. But then in June, July, August and September the rain kept coming. Lawns, trees and shrubs grew faster than ever.

So how does this tie in with Junipers, Leylands and hollies looking so poor this year? Plants get ready for winter by slowly shutting down each fall. Decreasing daylight hours and cooler temperatures cause the plant to harden off for winter. Last year, the fall stayed warm with plentiful rain. Plants still kept on growing almost as rapidly as they did all summer. Warm temperatures remained through the first week of December.

Then a cold snap with snow hit us the second week of December. It stayed below freezing most of the time until February. Tips of plants that hadn't hardened off by December were subject to this freezing temperature. They stayed green all winter since they were preserved by cold weather. Once warmer temperatures returned in March, it I became apparent there was a lot of damage to the tips of Junipers, Leyland cypress and holly. The tips were dead. This is called Winterburn.

Winterburn usually is found. on evergreens following a very cold winter. Last winter wasn't extremely cold. But when unusually heavy rainfall combines with warm weather lasting well into fall, you see winterburn.

Most of this year's winter-burn injury will be a memory. The best way to treat plants with Winterburn is to prune dead branches away. Junipers and Leyland cypress may take a couple years to fill in where there was significant dieback. It will be your judgment call whether to replace your plant or wait a couple years for the plant to recover.

Plants have a remarkable way to recover from adversity. Sometimes they need our help. Pay attention to anything unusual this year. Let's hope for a normal summer.

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