I was walking with a friend at Smale Riverfront Park this December and we passed large plantings of perennials, grasses, and shrubs. Nothing was cut back or cleaned up, it was wild and messy. I thought it looked fantastic, but my friend wondered why nothing had been done to tidy up the plantings in the fall. After giving her a pared down explanation of overwintering beneficial insects, feeding wildlife, and winter interest I realized this might be a good topic to review for our own landscapes.
If you are trying to decide what to cut back this winter based on wildlife as well as aesthetics let’s look at some do’s and don'ts.
Annuals – These are easy. As soon as heavy, frost hits them and they look terrible, tear them out and throw them in the compost.
Ornamental Grasses – LEAVE THEM UP! It drives me crazy to see all these beautiful structural winter pieces cut down in the fall. The only ones to cut down early are Miscanthus as they make a huge mess with late winter/early spring winds (I do not use these much as there are so many amazing native cultivars available that are easier to maintain – Panicum, Little Bluestem, Big Bluestem, Prairie Dropseed etc.). Cut down all grasses in late winter/early spring.
Perennials – Since prairie design is currently a focus we often have native perennial plantings that we don’t know what to do with in the winter. A few guidelines:
If it looks structural or interesting even without flowers leave it up (Globe Thistle, Baptisia, Sedum, Joe-Pye Weed and anything else you like the look of).
If it feeds the birds let it be (Rudbeckia, Purple Coneflower, Heliopsis etc.).
Beneficial insects may use the stems of perennials to overwinter (Joe-Pye Weed, Purple Coneflower, Ironweed, and Asters). They also use leaf debris to shelter during the cold months. See this link for more info: http://www.nativenurseries.com/blog/2022/2/15/nesting-and-overwintering-habitat-for-beneficial-insects
There are perennials that are prone to diseases that need to be cut down and cleaned up. Some examples: Bee Balm, Tall Garden Phlox, Peonies, Hosta, and Daylilies. Do not compost these debris.
So, if it is disease prone, doesn’t create visual winter interest, feed anything or provide a home then go ahead and cut it down. I compromise in my yard with a cleaner cut back look in the front and wilder “prairie” areas in the back that I leave until late winter/early spring.
Shrubs – If it has berries for the birds leave it be (Chokeberry, Winterberry Holly, Viburnum etc.). If it is an early spring bloomer do not prune in the winter as you will cut off all the buds for the upcoming season. If it regenerates from the ground up then cut it back or if you want to control the size of the plant winter is a great time for hard pruning.
I like the look of tidy beds, but I also appreciate leaving Mother Nature alone and giving myself a break on landscape maintenance. Some areas of my yard are more manicured and others are more wild depending on location and views.
If you want to dig deeper into overwintering your yard for wildlife then drop this link into your browser for a great resource:
https://xerces.org/sites/default/files/publications/18-014.pdfn