April 30, 2014
Many people have come into the store with a question about shrubs. The question always centers on the fact that they have a plant that appears to have died over the winter. Often the shrub is a rhododendron, holly or boxwood. In almost all the cases, it is a broadleaf evergreen. Let me tell you what I think happened to these plants.
If you remember back to last year, we had a certain amount of rain during June. The broadleaf evergreens put out new growth and then settled in for the summer. During early July we had a long stretch of very hot weather. The summer as a whole was very dry. If you couple the heat with the lack of rain, the soil became very dry. This lead to damage to the roots of the broadleaf evergreens and most other plants that were planted in your yard. During the fall, the broadleaf evergreens take up water and store the water in the leaves. This helps the leaves to survive the dry winds of winter. The problem was, the damage to the roots prevented the plants from taking up the water that they needed in order to survive the winter. If you remember, we had a cold and windy winter. This lead to damage to the leaves of the broadleaf evergreens. In fact, I am hearing that some of you lost perennials and other plants during the winter. My feeling is that putting together a hot and dry summer, followed by a cold and windy winter lead to a lot of damage to the plants in all of our yards.
The question now is, “Are my plants dead? ” If you have broadleaf evergreens that are damaged, you should check to see if the plant is dead. You do this by taking your fingernail and scraping a bit of the bark on a few of the stems of the plant. If you see green under the bark, the plant is still alive. If you don’t see green, try scratching lower on the branch. If you eventually see green under the bark, you will know that the part above that area was killed by the winter. If you find the green near the top, you can give the plant some fertilizer and see if you can get that damaged root system growing again. It is not unheard of for a plant to drop those damaged leaves and to put out new leaves. If the damage is part way down the stems, you can prune out the damaged area and give the plant some fertilizer. This will encourage new growth and allow the plant to fill in those spots that were pruned back.
The worst-case scenario is that the plant died over the winter. You should dig up the plant and replant a new plant. Before you put a new plant in the ground, you should check the soil to make sure that the soil has enough moisture holding capacity to prevent the roots from drying out during future dry periods. In the case of the broadleaf evergreens, you need to be not creating a situation where the roots are going to be constantly wet. This can lead to diseases that will kill the roots. Depending on the type of soil you have in your yard, you may need to add compost to the soil or you may need to remove the existing soil and add a mixture of soil that will promote a strong root system.
The other thing that I have found is that in many cases, the plants that were damaged or killed by the winter were plants that were not protected against the winter winds. Many customers told me that they meant to spray the plants with an anti-desiccant spray or they meant to wrap the plants with burlap. I guess this could be called a life lesson in gardening. Since we never know how bad the winter will be, you have to protect those plants in the fall.
Well, that’s all for this week. I’ll talk to you again next week.