Readying the Gardens for Winter

In Fall, Gardening, News, Perennials, Tonkadale Greenhouse, Trees and shrubs, Winterby Megan Nichols8 Comments

The first day of Fall has come and gone. The temperatures are telling us it’s time to think about tucking in the gardens for a long winter’s nap. We couldn’t ask for better gardening weather (minus the rain), and this is the best time to get a jump on the spring gardening season, too. After all, 2020 starts now!   

To Cut, or Not to Cut?

Cutting back the perennial garden does make for less work in the spring, but there are some benefits to leaving select plants upright. Sturdy plant stems can help hold snow and mulch in place when the winter winds get wily. Grasses and flower heads provide winter interest and some will attract birds. Native bees will winter-over under bunching grasses, and there are beneficial bugs that will hibernate in the hollowed out stems of some plants. It’s up to each gardener to decide what works best in their landscape and for their time.
There are some plants that should be cut back because they don’t really provide any benefits through winter and can just be generally messy (and in the case of Hosta, gross) to clean up in spring. Other plants should not be cut back at all, except in the spring and only for parts that have died off during the winter.

Cut Back

Cut to about 3” above the ground

  • Delphinium
  • Columbine
  • Hollyhock
  • Bleeding Heart
  • Bee Balm
  • Heliopsis
  • Peony
  • Coreopsis
  • Geranium
  • Hosta

Also cut any diseased plants or others that don’t offer winter interest.

Leave Alone

  • Bergenia
  • Heuchera
  • Yarrow
  • Aster
  • Geum
  • Gaillardia
  • Penstemon
  • Salvia
  • Tiarella

Spent flower stems can be cut, leave the leaf rosettes. In spring, cut off any dead foliage.

Divide and Conquer

Some perennials prefer to be divided in fall, so if these are overgrown or overcrowded in your gardens, now is the time!

  • Astilbe (use a hand saw)
  • Asiatic lily
  • Oriental lily
  • Lily of the valley
  • Veronica
  • Peony (use a hand saw)
  • Siberian and Japanese iris – dividing established plants will encourage more prolific blooms

Thin the Herd

Though beautiful, some plants can be a bit aggressive and tend to overtake the garden. Now is a good time to thin aggressive plants so everyone has a chance to grow next spring. Plants to consider include:

  • Nepeta
  • Phlox
  • Yarrow
  • Monarda
  • Black-eyed Susan
  • Mint
  • Lamb’s Ear

Do a Soil Test

Now is a good time to get your soil tested so you know what to add for best results in the garden next year. The University of Minnesota has a soil testing laboratory. Information on how to gather samples and accompanying paperwork can be found on their website.

Create New Gardens

Planning on a new garden for spring? Why not start now?  Mark out an area and cover with black plastic or a thick layer of mulch to kill any plant material. In spring, remove the covering and till or dig in compost and other amendments.

Edible and Annual Gardens

If your plants are past their prime and looking tired, go ahead and pull them now. If you’re still waiting on some tomatoes and carrots to ripen, or your annuals are looking good, feel free to leave them until after a frost. Be sure to cover edibles with frost cloth or old sheets if frost expected so the produce does not become damaged. Leave carrots and parsnips until after a couple frosts to make them sweeter, if you’d like.
After clearing out plants, dig in compost, leaves, and soil amendments to get the garden ready for next spring. Be sure to discard any diseased plant material in the trash and add only healthy plant material to the compost pile. 

Perennial Gardens

Once the ground has frozen, top dress beds with composted organic matter or manure. It will settle in with the spring rains and feed plants just as they’re starting to wake up and are hungry for nutrients.
To give your plants the best chance of making it through winter give them an extra blanket for protection. A chunky layer of fallen leaves, straw, or marsh hay will keep plants protected in the event of extreme cold and lack of snowfall and prevents an untimely freeze/thaw cycle in the event of a January thaw.  

Trees and Shrubs

Be sure to keep watering, especially anything newly planted. Trees and shrubs with young, tender bark should have trunk wrap to protect from varmints and harsh winter conditions. Some small varmints will eat all the way around a tree’s trunk, which causes girdling and death for trees.

Remove Buckthorn and other Weeds

As the days get cooler plants begin to turn color, but Buckthorn will remain green for a while, making it easier to identify. Cut and apply Bonide’s Stump and Vine Killer to kill buckthorn. Add a bluing agent (this can be found at most grocery stores and co-ops) to dye the product so it’s easier to identify where you‘ve already cut and daubed, especially if working in an area that was previously treated but where some left over roots send up shoots.  
Now is a good time to apply weed killer to the lawn and carefully apply around the perennial beds. Plants are responding to shorter days and taking up nutrients more quickly, so they’ll also take up herbicide quickly.


Relax and enjoy your time in the garden in Fall. The weather is incredible, the temperatures are comfortable, and a garden getting ready to hibernate is full of changes that are a joy to experience. Happy Fall gardening!


  1. thanks! great information.
    i’ve purchased some bulbs for fall planting. i’m planning on waiting as long as possible to plant though, as it seems the ground is too wet. am i right, and is there anything i can do to help the bulbs because of excess moisture?

    1. Author

      Spring blooming bulbs do best with a little time to establish roots, but not so much time that they have a chance to send up shoots and leaves. It’s also best to wait for the soil to cool, which is should be after cool temps last week and coming up. Take up a handful of soil and lightly squeeze – if water runs out, it’s too wet, and if it doesn’t form a ball it’s too dry. The sweet spot is when the soil will form and hold a ball shape but easily falls apart into chunks when pulled or poked. If the soil is very heavy and contains a lot of clay, amend with compost to improve drainage and protect bulbs from sitting in water.

    1. Author

      Boxwood can be trimmed any time. We recommend wrapping them in burlap to protect from harsh winter wind and sun. For roses, deadhead and prune back any dead or damaged wood and any unruly stems to give the plant a tidy appearance. Prune winter damaged and dead stems again in late winter before the plant breaks dormancy, around the end of March or beginning of April. Late winter is also the time to thin the center of the shrub and remove any crossing canes.

  2. When is the best season to plant rose bushes? Fall or spring?
    Is there a better brand for Minnesota weather and do you carry it?

    1. Author

      Roses are best planted in spring but can also be planted in fall. There is a line of roses called Easy Elegance that have some excellent roses for our area and we do carry some of those varieties. There are also Drift, Carpet, rugosa, and some climbing roses that are hardy for our zone. Just a few of the pretty ones in the Easy Elegance line include Campfire, Screaming Neon Red, and Sunrise Sunset. We will have roses again in Spring 2020.

  3. How do I prepare hydrangeas for winter.
    When and how should they be trimmed.

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