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Trees, shrubs and lawns all have different watering needs

Mature trees look so sturdy and invulnerable, it can be hard to imagine that they need to be treated as delicate infants until they are well established. Several readers have recently written to me with questions relating to tree care...

QUESTION: “We moved into a new development, and many homeowners are unhappy with the condition of our trees, shrubs, and lawn. I think part of the problem is in the watering. The sprinkler systems were set to provide water to the sod and the same set-up for the shrubs and trees. The junipers are looking quite good, but the yews are all turning brown and dying. They are then replaced with another after the year; no consideration for why.

“We are approaching our one year date. The trees out front on the easement are watered when the grass is. I don't think they got a good start last July when they were planted. My concern with them is that there are branches in the middle area that are bare and when pruned out, the tree will have an unattractive shape. Many trees have a bare "branch" sticking straight up the top. Should this be cut off? I don't know whether to hose water these trees deeply. Should I fertilize around them? They have a heavy layer of mulch around them.” – Beverly Fulkerson

ANSWER: Yes, you will need to prune the dead parts out of the trees and maybe begin a new “central leader” if the tree dictates it. You are of course correct in assuming that especially newly planted trees need different water requirements then grass. With grass you are only watering the top 3 to 4 inches, whereas trees need deep watering. I suggest you water evergreen shrubs only when they need it. These shrubs also require good drainage so as not to stand in water. I suggest that you look up some of the water requirements for certain plants on the Web. You can also find columns on watering trees at my Web site. Go to www.landsteward.org and click on the Plant Man heading.

QUESTION: “I noticed a white powdery substance on the lower branches of my Kwansan cherry. I washed them with Sevin soap and now I noticed some leaves are turning yellow and falling off those lower branches. I also have a wide split on one of the main branches coming off the main trunk. What precautions can I take to correct the conditions?” – Frank M.

ANSWER: The Sevin soap solution should have nothing to do with the leaves turning yellow and falling off. It could be you were a little too rough during the washing process and somehow disconnected the leaves just enough to do this. However, the split trunk may be the culprit. If the trunk has been split for any length of time there is probably little that can be done. You may want to contact a local tree expert or your Extension service for this one. For readers who are not familiar with it, Sevin is a brand name for an insecticidal soap containing carbaryl, which is also marketed under various other names and in different degrees of toxicity.

Reader Drew Denham has a response to an earlier reader comment in this column. Drew points out that catalpa trees can be found growing all over the world and not just in the Southern United States. He notes that on a recent trip to Germany he visited a castle that had several catalpa trees growing on the property. I can vouch for Drew’s assertion. On a recent visit to Europe, I saw a spectacular catalpa tree in front of the cathedral in Rochester, England. Very old and gnarled, the tree is now protected from young climbers by iron railings and is quite a tourist attraction!

The Plant Man is here to help. Send questions about trees, shrubs and landscaping to [email protected] For resources and additional information, or to subscribe to Steve’s free e-mailed newsletter, go to www.landsteward.org