What do you do?
You pinch back perennial plants or thin out stems.

How do you pinch back plants?
When a perennial, such as a chrysanthemum, gets to be two inches tall, you cut all the stems down to one inch tall At the “pinched back” point, one stem will branch out to two. When those two new stems get to be two inches tall, you cut them each back to one inch. You keep doing this until July 4. Then you have a well-formed plant, with lots of stems to be covered with flowers. They are all the same height, too.

How do you thin out stems?
With asters or irises, for example, after a few years, the plants could benefit from “thinning.” With asters, you just remove one third of the stems. With irises, you dig the plants and cut the root up into pieces. Then plant the pieces. Magic: more plants and more flowers.

Are there other techniques?
Yes. With Phlox paniculata [Summer Phlox], you leave the center stems tall, cut the middle ring stems shorter and cut the outer rings to the ground. If you are very strong-minded, you can thin out some stems as well. [I prefer to think of grey foliage as fancy variegation.] You then have blooms at different times.

Why do you want to do this?
You can just forget all this and enjoy your perennial plants. You can also make them happier and make them produce more blooms. You choose.

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