I want to follow up and expand on last week’s discussion of drought problems, especially helping trees and shrubs deal with the hot and dry weather. As I indicated last week, lawns will go dormant and even if they don’t fully recover with cooler and wetter weather, we can quickly renovate a lawn back to its original condition. Shrubs, and especially trees, are another matter.

Trees take years to gain their mature stature, lawns take months. Properly placed trees reduce the energy needed to keep your house cool in the summer and warm in the winter. Lawns require a lot of work. The point that I’m trying to get across is that we need to stop wasting time and water trying to keep a lawn green and spend more time and effort in helping our trees and shrubs survive this weather.

We’ve gotten spoiled in recent years. The 1990’s were cooler and wetter than normal. We’ve kind of forgotten what 1988 and 1989 were like. We’ve forgotten where we live and what the weather can be like. (We’ve also forgotten what a nasty Kansas winter is like and we’ll get one of those again some year soon, too.) We also get lax and lazy and forget how important and valuable our water resources are. Now that we’ve all been scolded, let’s move on to what’s happening and what needs to be done.

Deciduous trees (those with leaves that fall off in the autumn) have the ability to go dormant in periods of heat and drought stress. We are seeing this right now. A lot of trees are shedding leaves already. This doesn’t concern me too much because it is happening so late in the season. By the first of August, most trees have stored adequate food reserves in their roots to get them through the winter and growing next spring. Most of our deciduous shrubs are the same way.

Evergreens (pines, junipers/cedars, spruces, etc.) do not have the ability to go dormant. Their leaves/needles keep trying to carry on photosynthesis. This requires water. If the plant doesn’t have water in the soil, it will use the water it has internally. If soil water does not become available it will literally burn itself up. This unfortunate situation is complicated because the plants give no obvious outward signs of problems. A deciduous tree will start to wilt when it is undergoing stress. You have a visual clue that it needs water. An evergreen doesn’t have this same early warning system. By the time we start to see visual symptoms, dying foliage, we’ve missed the time when we could do something by weeks or even months.

What all of these trees and shrubs need, or could use, is a slow soaking of the root zone. The critical root zone of most trees and shrubs is the top 12 inches of soil in depth and extending out from the tree about twice the distance of the furthest branches. Most lawn sprinklers will not do an adequate job of watering a tree. Root feeders too often put the water deeper than most of the roots are located.

Your best tree or shrub watering device is an open hose running a slow stream. Place an open hose under the tree running a stream about the size of a pencil. This is going to take a day or so to do a tree. Every few hours, go out and see how it is progressing. If you have water running everywhere, then the water flow is too much. Another option is to use a black soaker hose, run it in a spiral under the tree, then let it run for a day or two. Start with your evergreens (spruces first, junipers last) and then do your deciduous trees. This hot dry weather may continue for several more weeks. A good soaking now will insure that those trees and shrubs head into fall and winter in a less stressed condition.

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