Answer: The general rule of thumb when pruning any tree or shrub is to remove no more than one-third of the live growth at any one time. If your shrubs are totally out of control and in need of renovation, plan on reducing the size in several pruning sessions. You can prune it back now by about 10', then wait until next spring to prune it down again. If it is still too large, prune again the following spring. Rather than just lopping the top off, try crawling into the shrub and removing a few main stems or branches all the way to ground level. Then selectively prune some of the outside stems and branches. This will encourage new growth in the center which will grow the rest of this summer and early next spring. Then in the spring, reduce the size and number of the outer stems and branches. This will allow more light into the center of the plant (where new growth will already be) and will encourage additional growth. By the following spring you should be able to remove the remaining old growth and you'll end up with a renewed shrub (from the inside out). Best wishes with your pruning project!
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