Extension Service Garden Hints

A dead tree or shrub? Learn from a post-mortem analysis

CORVALLIS - Do you have a tree or shrub that just didn't make it through the winter? There are many reasons a woody plant dies, explained Barb Fick, home horticulturist with the Oregon State University Extension Service.

Think about your deceased shrub or tree's life. Sometimes a "post-mortem" analysis can help you learn how to better care for a tree or shrub next time around.

Consider the weather. It was a stressful winter, with heavy snow pack and ice in many areas of the state, causing a lot of limb breakage. Were there rapid changes from warm to cold? Temperature fluctuations can sometimes stress a woody perennial enough to kill it, especially if that perennial is not a hardy variety or is not well-established.

Like a human being, a tree or shrub can die from a disease or pest infestation. Next time, take a sample of the ailing plant, before it dies, in for an examination by a horticulture agent or Master Gardener at your local county office of the OSU Extension Service.

The cause of death might have been related to its care – or lack thereof. Think about some other factors in your expired tree or shrub's life history. Did you plant it correctly? If you did, you took the container off and gently loosened matted roots. You also used the same soil you took out of the planting hole to backfill the hole and didn't plant it too high or too low in its planting hole.

Did you fertilize it too much or not enough? If you mixed a handful of chemical fertilizer into the hole when you planted that tree or shrub, it could have fatally burned the roots. Try an organic fertilizer next time—rotted manure, compost or an organic mix is less likely to burn the roots of a woody perennial. Or you can wait to fertilize until after the plant begins to establish.

Did you plant it where the drainage was poor? A common reason for shrub and tree death is poorly drained soils. The roots become waterlogged and die. To improve drainage, add lots of organic matter such as compost over the entire area. For very poorly drained soil, consider building a raised bed.

Did you water it enough last summer? Newly planted shrubs and trees don't have extensive root systems, so you need to water often at the base of the plant. Water slowly and deeply. Pay special attention to any plants you have growing under the eaves of the house—they receive very little moisture and can dry out easily, especially in years with little rain.

If the plant had pale green, undersized foliage and little growth last year, and has never been fertilized, it may have just expired for no good reason at all.

By: Carol Savonen
Source: Barbara Fick

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