Answer: Caryopteris or Bluebeard should not be trimmed back in the fall. Instead, wait until mid spring when you will first trim away any winter damaged stems. Then shape the plant by trimming it back about a third to a half or even more. If winter has been harsh, you may end up trimming the plant back almost to the ground.
Most sweet peas are annual vines meaning they die at the end of the season and are replanted each spring. The rather uncommon hardy or perennial sweet pea vine (in case this is in fact what you have) will continue to grow and bloom through the cooler months of fall and will begin to grow again very early in the spring. If needed for size control, trim it back as hard as you need to in late winter. It can also be trimmed back during the growing season if it begins to grow out of bounds.
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