This August, we have seen more rain than normal, which has allowed for huge savings on irrigation. Even so, foliage may look dry and shriveled, and sometimes it has gone dormant prematurely. All are measures taken by the plant to survive the heat with relatively low rainfall. In the event of dry conditions, please continue to water as regularly as you can. The shallow rooted evergreens may not have drooping leaves, but I can assure you they are feeling the stress just as much as your Hydrangeas.
REMOVE DAMAGED FOLIAGE
Many summer stressed perennials will perk up during these fall months. If you remove the old foliage, the new foliage will look like a brand new plant. If your herbaceous Peonies have succumbed to powdery mildew, do cut them back at the base. Other perennials with powdery mildew should be cut back to 3” ht as well. When sprucing things up for the fall, keep in mind the effect you want during the winter months. The black seed heads of Rudbeckia are quite striking against the snow, and the foliage of ornamental grasses is graceful blowing in the wind. Dormant foliage will also provide another layer of insulation against the cold, and a habitat for wildlife. It is your personal taste that matters the most.
WARNING ABOUT WOOD POPPY/STYLOPHORUM DIPHYLLUM
I have some Wood Poppy in a prominent location, so I try to keep it looking as fresh as possible. Unfortunately, the foliage usually turns brown in August, but if I cut it back to the ground, I am rewarded with fresh green foliage in the fall. When you cut the stem, you will notice that the stem is hollow, and bright yellow sap will begin to bubble along the edge. This sap will quickly stain your clothing, and cause severe burning in your eyes if any liquid should find its way there. Last summer, I rushed to the emergency room afraid that I was about to go blind. Be sure to wear protective eyeware and old clothing.
This is also a perfect time to install new plants. Though most should be planted before November, there are quite a few deciduous trees and shrubs that can be planted even in November or December.
September is also a good time for pruning trees and shrubs that bloom on new wood. The new growth encouraged by pruning will have sufficient time to harden off before the winter cold settles in our area. Plants that bloom in the spring on the previous season’s growth should be left alone until after blooming in the spring. Most notably, this group includes Lilac, Viburnum, Spirea, and most of the spring flowering trees. If you are unsure, please send me an email, and I’ll be happy to advise which group applies.