Answer: These are pruned carefully and faithfully each spring. The process involves breaking or snipping off a portion -- but not all -- of each individual growth tip before it expands. (These tips are also called candles.) The more you remove, the more it will branch in the future and the less the plant will grow that coming year. You can maintain them at a very slow rate of growth this way. But if you miss pruning, it will grow significantly that summer.
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