Planted outside in a warm area, it can get to be 8-9’ tall. In a colder area, it will be smaller, about 5’ tall. Now, early spring, is the best time to prune. However, it won’t hurt the plant to prune it later in the year but you run the risk of cutting off next year’s flower buds if you cut it way back. The fun thing about thryallis, is that you can prune it in topiary shapes and really make it an accent plant in your garden! Or, prune several into a hedge and use it as a backdrop to your other plants. How much to trim off, depends on what size you want it to be. Keep in mind, that if flowers on the tips of the branches.
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