Cutting Back on Work
Sonia Uyterhoeven is Gardener for Public Education at The New York Botanical Garden.
Have you ever noticed how some plants look just great in the fall? They are nice, neat and full. Generally, that is not the natural growth habit. A little care has to be taken earlier in the season to ensure their fullness, and now is the time.
You can pinch your mums starting in mid to late May to give them a nice full shape. An easier option is to wait until mid-June and just sheer them back by about half. I take a good pair of hedge sheers and cut them so they look like nice, rounded domes. They will keep the shape as they grow throughout the summer.
If you don’t have sheers, just take your bypass pruners to make your cuts. Remember, gardening is not an exact science, so just shape them so they look nice. What you are doing with the cuts (heading cuts) is encouraging lateral shoots (side shoots) to branch out and create a more compact, full shape.
With our tall Korean mums, which are the envy of every visitor in late October through early September, we cut them back twice. The initial cut is in mid-June and the second cut happens three weeks later, around July 4. The holiday is a helpful reminder of the cut-off date. If you continue sheering these late season bloomers throughout the summer, they will flower too late in the season and get knocked back by the frost.
Asters also get cut back in this fashion. Often we further support our asters by placing a peony hoop over them early in the season. These hoops are raised as the plant grows to give added support.
You don’t have to limit yourself to these two classics. Beebalm (Monarda) responds well to this treatment, as does Joe Pye weed (Eupatorium), Helen’s flower (Helenium), and a whole host of perennials.