Answer: This shrub can be pruned right after it blooms in the spring. If you selectively remove the oldest branches on a regular basis, that will help thin it. It is a large plant, though, growing to about 12 feet tall and wide, and is not a naturally tidy looking plant, so it may be a case where it is simply too large and unkempt in habit for your landscape. I should also mention that this plant was originally introduced by the Soil Conservation Service and has since been found to be an invasive in many areas -- as it spreads very quickly by seed and displaces native plants. You might want to check with your local county extension and/or your local professionally trained nurseryman to see if something else might be more appropriate.
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