The days are getting shorter and the temperatures are dropping.  Inside our cozy homes, we bring out the blankets and switch on the heat, secure that we can survive the winter in safety and comfort.  Outside, our gardens are preparing for winter too.  Some signs are obvious - deciduous trees and shrubs entering dormancy and shedding their robes of red and gold, holly berries changing from Halloween orange to Christmas red, and herbaceous perennials losing their luster until finally collapsing or becoming a stand of stark blackened stems.

Other transformations are slowly taking place deep within their cells, complex interactions of plant hormones, proteins, and enzymes, in response to chilling and decreased sunlight.

But can they do it all alone?  Do they need our help to endure winter's adversities, or will Mother Nature safeguard them until spring returns? The answer to both questions is essentially yes.

In general, Mother Nature has strategies in place, but there are things you can do to ensure all goes well.  Most plants prepare for winter by entering a state of dormancy triggered by cooling temperatures and shorter days.  This is a gradual process, however, and greatly fluctuating temperatures during this period can interfere with a plant's ability to protect itself.  

In addition, all plants are not equally adapted to cold weather, which is why we have established different hardiness zones.  if you are choosing plants that are within the hardiness limits for your zone, they should be able to withstand the winter with little help.  Toward that end, it is important you refrain from pruning woody plants late in the season.  Pruning prompts tender,  new growth highly susceptible to frost damage, which in turn provides an entry point for insects or disease.

You can assist Mother Nature by applying a 2- to 3-inch layer of mulch, but only AFTER one or two hard frosts.  Applying mulch too soon warms soil temperatures at the precise time plants are attempting to enter dormancy, meddling with the acclimation process.  The mulch is intended to prevent frost heave, which can push sensitive or newly-planted perennials out of the ground, breaking and exposing the roots.  Remember to mulch around, not on, perennial crowns, or rotting may result.  Tender perennials (those planted out of zone) that need extra protection can be covered with evergreen boughs.

The last task you should definitely perform this time of year is to remove the foliage from any plants that suffered from disease during the growing season, including any leaves that may have previously fallen.  Fungal spores can survive through the winter to strike again the following year.  Be sure to dispose of this material and DO NOT compost!

Optional garden winterizing duties include:

  • cutting back herbaceous perennials and grasses
  • removing dead annuals
  • preparing new beds for spring
  • protecting tender shrubs
  • lifting and storing tender bulbs

The first three will either need to be done now or in early spring before growth resumes - for the most part, it is your choice.  Some perennials provide valuable food and cover for birds or have attractive winter silhouettes which look striking blanketed with snow, while others just look messy and annoy your fussy neighbors.  Leave evergreen perennials and the green basal foliage of plants with tall flowering stems.

If you are planning to start a new bed in spring, you will save yourself much time and trouble by doing a little work this fall.  Simply place newspapers 10 sheets thick over the area, then cover with a layer of compost, finish with a 2-inch layer of mulch and water in.  You might consider applying a granular pre-emergent herbicide (such as Preen) on top of the mulch to prevent any weed seeds blowing in from germinating.  Of course, skip this if you're planning on direct seeding anything in this bed!  By the time the weather warms in spring, all the grass and weeds should be dead and the papers decomposed, ready to till in.  

The last two chores will need to be done now if you choose to do them at all.

Saving your bulbs is not hard, can save you a lot of money and will provide you with earlier and larger plants for the coming season.

  • Caladiums, non-stop begonias, elephant ears, cannas, and dahlias are prime candidates

Simply wait until the first hard frost blackens the foliage, then dig up the bulbs or rhizomes, wash off the soil, let them dry for a day or two.  Once they are dry, cut off the foliage and store them in a paper or net bag (no plastic) in a cool, dry spot - much as you would store a potato.  Check once a month to be sure they are not drying out too much - if they're very dry you may add some moistened peat moss or mist very lightly with water.  If you have space, you can start your bulbs in late winter or early spring in a warm, bright spot inside, then transplant into a garden after last frost.

Tender shrubs can be protected by wrapping with burlap and twine or by creating a wire cage around the plant and filling with dry leaves.  Do not use plastic, as this may hold in too much heat on warm sunny days.

Whether you decide to help just a little and enjoy the natural look, with snow-covered grasses a backdrop for foraging juncos and white-throated sparrows, or get down and dirty with a full cutback and cleanup to please the neighbors, rest assured that Mother Nature will do her part to be sure her children are safely tucked in 'til spring.  Just remember, what you don't do now, you'll do then!

In conclusion...

What must I do to winterize my garden?

  • Mulch:  apply a 2- to 3-inch layer around plants AFTER hard frost to prevent heaving
  • Remove damaged/diseased leaves, stems, branches; do not compost diseased foliage
What can I do now OR in early spring?
  • Lift and store tender bulbs after first frost.  Remove soil and store dry bulbs in paper bag in cool, dry spot
  • Protect tender shrubs with burlap & twine or wire cages filled with leaves
  • Remove dead annuals & compost
  • Cut back perennials, leaving those with attractive seedheads or seeds for birds
  • Plant cold-hardy bulbs (tulips, daffodils, hyacinths, etc.) before ground freezes
  • Empty and store terracotta and glazed ceramic pottery
  • Bring in houseplants - most before temperatures drop below 50 degrees F
  • Start amaryllis and paperwhites for holiday
Perennials Best Cut Back in Fall
  • Daylily, veronica, brunnera, monarda, peony, garden phlox
Perennials Best NOT to Cut in Fall
  • Kniphofia, chrysanthemum, Frikart's aster, agastache, Montauk daisy
Plants to Mark Location - Late Spring Emergent
  • Butterfly weed, balloon flower, perennial Hibiscus
Plants with Evergreen/Basal Foliage NOT to Cut
  • Heuchera, Hellebore, autumn & tassel ferns, Shasta daisy, Geum, oriental poppy, Dianthus, sea thrift, Penstemon Husker's Red, and some Euphorbia, hardy geranium, and Salvia species