Preparing Perennials for Winter

It’s September.  The nighttime temperatures are beginning to drop.  The morning air is crisp and cool.  The summer sun is setting, fall is coming, and winter will soon be here.  It’s time to begin thinking about preparing your landscape for winter.  The question is, “What do I have to do to prepare my perennials for winter?”

First of all, what the heck is a perennial?

Hosta. Photo by Wanette Lenling

One of the questions that first time gardeners always ask is what is the difference between a perennial flower and an annual flower.  It’s simple. Annuals have to be planted yearly (annually) and perennials come back up year after year (perennially). Annuals include such flowers as petunias, impatiens, and alyssum.  Perennials include such garden favorites as daylilies, hostas, and coral bells.  Whereas annuals live for one season, set their seeds and die,  perennial plants hibernate during the winter only to burst forth in the spring with new growth when the weather warms.  There is also a whole other set of plants called biennials that act like both perennials and annuals! I won’t cover biennials here as I will tackle that subject in an upcoming blog so stay tuned!

Hollyhocks, are a common biennial.    Photo from

In the fall, annual flowers  can be dug up and discarded into the compost pile. Their life cycle is complete and they will need to be replanted either by seed or as transplants the following spring.  So then, the question remains: “What do I do with my perennials for the winter?”

Do I have to cut down my perennials in the fall?

I have both cut down my perennials for winter and left them up. As a naturalist organic gardener, I prefer to leave my healthy perennials uncut for winter when I can.  In nature, as plants die back in fall, the base of the plant is insulated from the cold with the plants own dead leaves and other garden debris like fallen tree leaves.  Snow acts as a secondary insulation keeping the ground temperatures stable and creating a barrier between the plant and the biting cold air. With a moderate amount of snow cover, the ground temperature, even near the surface, will actually hover just below freezing.  This is why water pipes do not freeze when they are buried underground!

For a more concrete example of layered insulation, think of how a home is insulated with multiple layers of insulation.  There is siding on your house under which is sheeting to keep out moisture and drafts and then there is fiberglass or blown insulation in the walls between the studs.  Mother nature uses the same concept of multiple layers of insulation to keep plants protected from harsh winter weather.

What do I need to do to protect my perennials when I cut them down for winter?

It is not uncommon for gardeners to cut down all their perennials in fall.  It keeps your yard looking neat and tidy and prepares the landscape for next spring.  And, if you live in an area with a Home Owners Association, you may be required to clean up your landscape in the fall to stay within the rules of the HOA. There is nothing wrong with cleaning up your landscape in the fall.  In fact, if you have had any insect, bacterial, or fungal infestations, you definitely want to remove the greens from at least those plants. Throw this plant material away rather than putting it in the compost pile as it may spread the problem onto next year’s landscape.

If you choose to cut down your perennials, it is a good idea to cover them with a layer of mulch several inches thick to protect them from the winter air. The mulch can be anything from purchased wood mulch to straw or tree leaves. Leave the mulch on the perennials for the duration of the winter.  In the spring, carefully rake the mulch away, uncovering your perennials, to allow the spring sun to warm the ground.  Your perennials should wake from their slumber and begin to grow.

It is especially important to cover tender perennials, even if you don’t cut them off.  A tender perennial is basically a perennial that a gardener is attempting to grow in a climate zone with harsher winter temperatures than what is generally recommended for that plant.  For example, a zone 5 perennial grown in zone 4 would be considered a  tender perennial in zone 4.  The plant will need much more care in zone 4 in order to help it survive the winter, if it will at all. (Please see the following link to learn more about your growing zone:  USDA Zone Map  ) If you are attempting to grow a plant in a colder zone than is recommended, please do a search on the particular plant you are attempting to grow in order to find out what professionals or other gardeners recommend for winter protection for that specific plant in your specific area. It may save you the heartache of having to replace your plant in the spring.


Perennials with a purpose.

There are some plants you may want to consider leaving up for the winter simply because of their striking beauty or usefulness.

Red Twig Dogwood
Red twig dogwood photo found at

Upright sedum such as ‘Autumn Joy’  and ornamental grasses like ‘Karl Forester’  look gorgeous in the winter landscape.  Dried sedum flower heads  with a soft dusting of snow covering them add interest to the winter landscape and the movement of ornamental grasses in the winter breeze surrounded by snow is undeniably beautiful.  Another noteworthy exception is red twig dogwood.  Even though it is a woody shrub and not a perennial flower many people cut it down in the fall. It is definitely worth leaving up for its striking red winter color.

Some other perennials that you may also consider leaving up are flowers with seeds that are consumed by birds like coneflowers and black-eyed susans. Coreopsis, or tickseed as it is commonly called, is also a favorite of winter wildlife.  The birds will love the winter buffet and you get to enjoy the view!

A little preparation in the fall on your part is all it takes to insure that your plants have a great shot of surviving the winter weather.  It’s well worth the time and effort when you see those same plants bringing your garden to life in the spring.

Happy Gardening!


Quote of the Day

“The spring, summer, is quite a hectic time for people in their lives, but then it comes to autumn, and to winter, and you can’t but help think back to the year that was, and then hopefully looking forward to the year that is approaching.”

-Enya, Irish singer and songwriter





The Trouble with Slugs

Slugs are a shell-less gastropod related to snails. They can be found in most gardens, often hiding under rocks or in other dark, moist places during the day, only coming out in the evening to dine on your favorite garden plants. Holes in the leaves of your plants are a telltale sign of slugs in your garden. Occasionally, slugs will strip a plant of its leaves completely.  Slugs can leave your precious garden plant an unsightly mess or completely devastated.

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It’s easy to pick slugs off garden plants if you aren’t squeamish but it’s nearly impossible to find them all. There are some garden visitors that will help eradicate slugs from your garden like certain species of backyard birds, toads, and snakes. Domesticated birds such as chickens, turkeys, geese, and ducks also have a taste for slugs.

If you would rather take a more direct route to ridding your garden of slugs, there are many organic remedies that will do the trick.  Many garden catalogs and websites sell nematodes, which are a parasite that live naturally in the soil. This type of nematode is harmless to mammals, including humans, but it will kill slugs, snails, and some  ground dwelling insect larva.

Diatomaceous earth, which can be found at garden stores or online, will also kill slugs.  Diatomaceous earth is actually the fossilized remains of an ancient algae that is mined from the ground. It is comprised mostly of silica particles with very sharp edges.When the slug crawls through the powdery substance, it cuts the slug’s underside and causes dehydration leading to death.  Diatomaceous earth is safe for humans although care should be taken to protect the eyes and lungs when it’s applied. Follow the directions on the package for proper application.

Another means of killing slugs is beer.  Simply place a saucer or lid on the ground making sure the edges are level with the dirt. Then fill the saucer or lid with beer.  Slugs will climb in and drown during the night. Dispose of the old beer and replace it with new beer every day until the slug problem is gone. This remedy is one of the easiest to use.

If you don’t want to kill slugs but would rather only deter them from dining on your favorite garden plants, copper is the perfect solution. Place a wide ring of copper wire around the base of your plant making sure the copper ring is large enough to be on the outside of any leaves that may touch the ground.  If the problem is with a potted plant, place copper wire around your pot or purchase copper tape  from a garden store, garden catalog, or online. Copper tape works well on a pot because it sticks and won’t slide off like wire will. Copper keeps slugs out, however, it will also keep them in! Check your plant carefully  for a few days to make sure there are no slugs inside the ring of copper or on your potted plant.

These are just a few simple, safe, and organic ways to handle a slug infestation. I personally don’t mind slugs on my garden plants as I like to share, but if you are squeamish toward slugs or if you have a prized plant that slugs are destroying, one of these remedies may be the answer to your slug woes!

Happy Gardening!