Monday, November 3, 2008

Frost Tolerant Perennials

For some of us “Tree Hugging, Dirt Loving” gardeners here on the Front Range, the floral growing season is all too short. If it were up to us, we would like at least another month! Maybe we don’t want to fly south with the birds, or live in Florida, but we would like to eke out a few more days or weeks at the end of the season when some flowers are still blooming. Please?

There are a few annuals and perennials that do have tolerance for light frosts – other than the tough, ubiquitous Pansy we see in all the nurseries in fall and spring. Here are a few more to consider (nothing exotic): Bells of Ireland, Black-eyed Susan, Calendula, Callibrachoa, Coreopsis, Cornflower, Chrysanthemum, Dianthus, Ornamental Cabbage, Primrose, Roses, Rudbeckia, Snapdragon, Stock, Sweet Pea, and Violet. These will generally give us 2-3 weeks after the fall average (light) frost dates. If we have been diligent at deadheading during the summer, even the perennials in this group may still be blooming. These can be good little troopers in the fall, unlike Begonias, Impatience, and Portulaca, etc. that turn to mush or straw at the very mention of the word frost!

When planting, we also need to keep our little microclimates in mind – hillsides where cold air flows off, protected areas next to the house, or near heat-trapping brick or stone walls – the little “Zone 6” areas that are the exception to our Front Range Denver normal Zone 5 climate. Take advantage of any warmer areas you might have, and remember to harden off greenhouse-grown plants by exposing them gradually to our bright sunlight, wind and variable temperatures in early spring before planting them in your garden.

Posted by Jeffco Master Gardener Dave.