Pruning Perennials for Compact Growth

by Les & Jill
(Middleton, MA )

How do we prune perennials for compact growth?

This year, the residuals from recent hurricanes have resulted in our taller plants being scraggly and scrawny-looking. The heavy winds and rain have even caused some of our tall perennials, hardy hibiscus and dahlias (I know they are not perennials here in New England) to bend and break due to their inability to support flowers. Can we prune these plants early to make them smaller and more compact? If so, when is the best time to do this? What effect will this have on the blooms?

Thank you for your time and cooperation. We welcome any suggestions or recommendations you might offer and look forward to your reply.

Doug says that this is an old growing trick for many plants. It works well for those plants that produce flowering stalks from the leaf growth (think daisies) rather than plants that produce flowers from stalks starting at the base of the plant (thin daylilies).

So if the flower stem is produced on the upper part of the plant, this trick works.

When the plant reaches approximately 12-18 inches tall in early June, simply cut it in half (down to 9-inche) or remove all the top growth (remove 3-inches of the top growth) This will thicken the plant growth up nicely and will let it grow multiple stalks for flowering.

Having said that - if you do this with some plants such as Dahlia (yes, you're right it's an annual) you're going to get more blooms but each of these blooms will be smaller. Exhibition sized flowers of almost any plant are produced when the number of blooms is restricted.