Traditional gardeners will often tell you to cut back herbaceous perennials in fall. The main reason why people do so is to avoid the sight of brown or dying foliage on the plants, which some may consider to be unsightly.
But there are a number of reasons why, when herbaceous perennials begin to die at the end of the season, I do not cut back the dead and dying foliage but instead leave this in place to die naturally, or stand in place over the winter months.
To Provide Habitat for Wildlife in My Garden
The main reason that I choose not to cut back herbaceous perennials in fall is due to my desire to make my own garden as wildlife-friendly as possible. If I cut back all of my herbaceous perennials in the fall, then I would lose an important winter wildlife habitat. Herbaceous perennials that have gone to seed will often provide seeds for birds and other wildlife to eat. And dead or dying foliage standing into winter provides cover for a range of species.
By being too zealous in cutting back, we can deprive wildlife of food or shelter through the winter months. This is the main reason why, in the pursuit of a “tidy” garden, we should not be too quick to make our gardens less valuable to the creatures with whom we share our space.
In my opinion, the space in which I garden belongs to the other creatures that live there, just as much as it does to me, and I always garden with wildlife in mind. My view is that this is one of the most important things in an organic garden.
Working with nature makes things better for them and easier for you as the gardener. All that wildlife brings a range of benefits and can help you in many ways in your garden.
Dieback Returns Nutrients to the Soil
If we are too quick to cut back and tidy up beds and borders, we can also deplete the soil, since the materials we remove will not be able to break down and return their nutrients to the area of soil where they are grown.
Perennials left in place slowly break down over the winter. Of course, some stand longer than others, lasting into or even through the winter months with dead foliage or stems in place. But chopping and dropping or cutting them back in early spring, rather than in the fall, is a far better policy for wildlife and for long-term fertility.
Top Growth Protects the Roots of More Tender Perennials
In some cases, the dead or dying foliage on herbaceous perennials can be beneficial in protecting the roots of more tender species and make it more likely that they will survive the winter in colder climates.
With the protective layer of the top growth on these plants, which may stand even once dead for a time, the crowns of plants will be somewhat insulated against air temperatures and the ground may be less likely to freeze.
It Adds Visual Appeal Through Fall and Winter
One final thing to consider is that even once plants begin to die back, a herbaceous border can still be visually appealing—just in a somewhat different way than during active growth in the summer months.
While some may find brown leaves and seed heads unsightly, I personally enjoy the way the border looks as fall wears on, and into early winter. Though they can look quite unkempt and wild, seed heads, stems, and dying foliage are attractive in their own way. And in some cases, leaving seed heads on the plants offers the possibility for self-seeding, which can help in creating a lush garden that just keeps looking better and better each year.
As with everything in a garden, there are some exceptions. But as a general rule, for wildlife, long-term fertility, and a wilder visual appeal, I choose not to cut down my herbaceous perennials when they begin to die back in fall. Instead I leave them to die back naturally in winter or, if necessary, cut them back to give some breathing room to new fresh growth just before this emerges in the spring.
