Although we have a few weeks until the official onset of winter, it is always a good idea to think ahead and prepare in the world of gardening. In our climate we never quite know when that first hard frost will happen. Some people got a frozen night or two a couple of weeks ago, while others (like me) did not. With all of the microclimates in our area, “winter” will vary depending on our exact elevation and location. This nebulous first frost date can be challenging for sure, but my hope is that by learning some basics, you can get those gardens winter-ready sooner rather than later.
There are a number of tasks to accomplish going into winter for any garden, but for this week I think a focus on perennials is prudent. Hardy garden treasures like perennials should be lifelong companions, getting better year after year. As they approach dormancy for the winter, there are a number of things that we can do to protect them during the coming colder months. I know I have pontificated many times on my OCD tendencies and the internal battle of neat versus natural for many like me, but ultimately you need to do you. I ask that you try to keep in mind some benefits of both extremes and then make your own decisions of what to clean up, cut back or perhaps leave alone until March.
A newer term in horticulture is “temperennial”, which to me is a fancy word for a fussier specie that is right on the hardy line for us here in Western Washington (typically labeled as Zone 8 hardy). Two major plants that we use in our area in this category are numerous cultivars of either Hardy Fuchsias or Salvias. With both of these, a number of specific varieties exist that are hardy but others are marginally so, in all honesty. An exceptionally cold (or sometimes extra wet is even worse) winter will damage these plants. I grow many types of both of these and have found that NOT cutting them back in the fall is the best way to go. I would recommend leaving the woody stems alone and waiting until April to cut them back. You will hopefully see new green sprouts emerging from the wood here and there, at that point you can cut them back to your desired height above this new growth.
Typical perennials come in countless options, for both species and cultivars. To simplify things a bit, I am going to classify them into three major categories; sticks, mushers, and evergreens.
“Sticks”: Think of those perennials that are a little woodier, particularly with their flower stalks, like Coneflowers, Rudbeckia, Gaura, Peonies and many others. I might suggest leaving some of the sticks so you know where they are and do not trample them over winter. I sometimes even discretely pop a short stake in the ground, a reminder to my getting old brain that yes, there is a plant there.
“Mushers”: Think of those plants that melt away in fall, disappearing almost completely to the soil level. Hostas and Bleeding Hearts are poster children for these as they can often be scraped up and thrown into yard waste any time. Sorry to brag, but most of my OCD Hostas are already done!
“Evergreens”: Think about all of the cool perennials that keep their foliage over the winter; Hellebores, Bergenia, Lavenders, Epimedium and Heuchera just to name a few. These should have been cleaned up in August to look sharp all winter long, and then should be cleaned up again coming out of winter to shine through the growing season. Except for bad foliage and spent flower stalks, we leave these alone this time of year.
Now before I go any further, cutting things back is ultimately up to a conversation between you and Mother Nature. I would not rush out and whack everything back today, or tomorrow for that matter – waiting for a hard frost is best. Let your plants tell you when it is time! Also, remember that we are talking perennials here, not trees and shrubs. All evergreen plants should be left alone until after spring frost and deciduous plants should be done later than that, after determining if they are old or new wood bloomers. That is a topic for another day… Be sure to always use sharp, clean pruners when doing this to avoid smashing stems. Following your fall perennial pruning, consider some protection by utilizing these practices below.
Diseases: If I have any perennials (or other plants for that matter) that had mildew, rust, blight or any other issue, they are the ones that I focus on cutting early and removing all of the bad foliage out of my garden as soon as possible. Leaving diseased foliage on the ground is simply asking for the same issue to occur the following season.
Slugs: Any slug-prone specimens are the same as above to me – leaving the foliage at the base is an invitation for mama slug to leave a bunch of baby slug eggs. Cleaning these up and leaving a bit of natural slug bait (Iron Phosphate - think Sluggo) will help keep them slug free the following season.
Birds: Providing natural nesting material, shelter and seeds for food are all important to me, so leaving certain perennials for them to utilize is always a priority. This also includes the hummingbirds, as insects (protein) living amongst this winter debris will provide extra food for them.
Naturalizing Style: Many perennials like to go to seed in the fall. This will help the birds (see above) for sure, but these seeds will also stratify over winter and then sprout in spring, giving me more plants in my patch, if that is my desire. If it is not yours, then absolutely remove these seed heads to keep your plants contained.
Mulching: It all comes back to compost, as always! Good quality compost makes great insulation for perennials and is an easy way to protect the crowns of many. I go through almost every perennial in my own garden this time of year and once they are cut back, a copious mound of mulch is added to protect them. Then come spring, this mulch can be feathered out away from the actual crown, organic rose/flower food (and alfalfa meal) added, and finally re-covered by this same nutrient rich compost.
As you walk about your landscape this fall, formulate a battle plan on what should be done with your perennials. What will get cut back now and what will get left alone until March? What will need some protection from slugs? What will need mulching for additional winter protection? I might even add one more idea… Where do you need additional perennials to fill in any open garden spaces? With fall clearance sales at local garden centers in full swing, it is a great time to grab what I call pure garden potential (discounted dormant perennial value) that will thrive again come spring. Stop into your local garden center and speak with a Certified Professional Horticulturist about protecting your perennials. Asking the right questions will help you be successful. Grab some natural slug bait, some compost for mulch, set out that keeling pad, strap on the rain-gear and get going on your perennials. Try to remember to stay positive and realize that gardening is all about trials and tribulations. Roll with the punches from Mother Nature and maybe even consider lost specimens as opportunities, not failures - now a new perennial treasure can be added to replace that one that traveled to the great compost heap in the sky.
