Friday, October 22, 2021

Winter Prep Tips for Gardens and Trees

Kristina Kasik, Master Gardener, Gunnison, CO

We’ve already seen a few cold nights that have us forgetting about gardens and thinking about winter: splitting and stacking wood for the stove, buying better tires, prepping the plow, waxing those skis in anticipation of the slopes.  But the growing season is not exactly over, not just yet! There are things you can do still, before the snow flies and the ground freezes solid. 

This is the perfect time to plant.  No, I’m not crazy.  Fall is a great time to plant seeds and bulbs, and it’s sow easy!  Yes, pun intended.  Most of the perennial flowers that do well in our valley, such as penstemon and columbine, need that cold snap of winter to tell the seed when to germinate come spring.  Many annuals are the same, and putting those seeds down now will reward you with hardier plants that require less pampering than store-bought starters. 

Cosmos are a good example. Several gardening websites call them tender annuals, meaning they should not be sown until after danger of frost. Yet the cosmos I planted from seed three seasons ago keep coming up from the seed they produce and drop each fall. The seeds seem to “know” when to start growing and the resulting seedlings can tolerate light frost, unlike transplants. The blooms will be later in the season than transplants, but if you’re really itching for early color, let’s talk bulbs.  

As long as the soil is not frozen you can plant bulbs for your early spring crop of tulips, daffodils, alliums, crocus, hyacinths, and more. I find nothing more rewarding than seeing the hardy colorful blooms appear, even when there may still be snow on the ground.  Ideally bulbs should have a few weeks before the ground freezing to establish themselves so they will have a good strong start in the spring.  Let’s not forget about garlic, either!  This is the one “veggie” crop that you plant just like flower bulbs: in the fall. 

Don’t forget to water. Yes, water. This is a semi-arid climate, after all. Those bulbs you just planted need some water to get some roots going before the big freeze. The trees and shrubs you planted last year, the perennials you planted in the spring?  Yep, they want a drink, too.  

Sunny, windy days plus lack of rain wil wick moisture from the soil and from plant roots. The leaves may be gone, but that tree is not dead. After the leaves have fallen but before the ground freezes (not just above-ground frost - don’t worry about that) is the perfect time to give those trees and shrubs a deep watering, especially evergreens. 

Since evergreens keep their needles all winter, they are even more prone to water loss because of all that extra surface area. Younger or newly planted trees need more water than those that have had several years to establish a large, deep root system.  Not sure when to water or not?  Try to remember this: after the leaves, before the freeze, days above 45 degrees (I swear I just made that up). 

On a related note to watering, you can do a couple of things to prevent water loss leading to damage. Trees may benefit from some wrapping protection, especially those young evergreens. All winter long the sun’s radiation and the wind are pulling moisture from evergreen needles. Trees planted from a container or balled and burlapped typically have a much smaller root system than a wild tree of the same size would have. 

More top to less root means more water loss. Wrap the entire tree with burlap or a similar material, or create a screen on the south, southwest, and windward sides of the evergreen. Wraps should be removed in the spring but screens can stay in place for another season. 

Thin-barked trees such as aspen can suffer from frost cracks and sunscald.  Frost cracks will appear as vertical cracks in the bark, where sunscald will leave a sunken appearance where cells under the bark have died.  Both, in short, are caused by extremes of heating and cooling, and are seen on the south and southwest-facing sides of the main stems of very young trees. 

Both can be prevented by wrapping the trunk with a light colored paper, such as crepe paper, from about November through April. Start from the ground up to the first branch, overlapping the paper in a diagonal fashion.  This is only necessary for the first couple of years, until your new tree builds up a thicker bark layer. 

Mulching is another great way to prevent water loss and adds a layer of insulation to roots from extreme temperature changes. Snow is a perfect mulch, but since we can rarely predict when or how much snow we will get, mulching is a good idea.  

Perennial flower beds will appreciate a 2 to 4-inch layer after the last of the plants have died and turned brown. Those fallen leaves you raked up can be used here, or straw, or a bark or wood chip mulch. Newer trees and shrubs can be mulched as well, but never right up to the trunk or stem, that can hold too much moisture and cause rot. Make a ring around the tree, starting about 6 inches away from the main stem and end at the outermost branch tips. It's as simple as that.

Is any of this information interesting?  Like planting and growing and want to learn more? Never gardened before and want to start?  Consider taking the Colorado Master Gardener class this winter.  To learn about the Colorado Master Gardener program visit



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