Plants in Winter

When considering winter in Colorado, I often want to write that plants rest, but in fact, I don't think that is true. A rest is defined as a time to relax and recover strength. Plants drop their leaves and go dormant in winter because they cannot move ice in their tissues, let alone use it to grow. Furthermore, water expands as it freezes, so freezing rips up most cells. There is no recovery of strength in winter, only waiting out an impossible season.

That said, the plants that survive through the winter are an elite minority.

Visiting Colorado--Fall Mountain Scenes

It is fall in the Rockies. The aspen leaves are turning colors. As I write this in early October, Trail Ridge Road at the top of Rocky Mountain National Park is closed due to snow. It should reopen, but, clearly, it is winter now at 11,000 feet. Where I live, at 5,000 feet, we have not yet had a frost. As cold temperatures move down the mountains, aspen and other deciduous trees will change color and then lose their leaves at successively lower elevations. Lots of opportunity to enjoy the spectacle.

Flowers of the Colorado Winter

pansies, December 16

Its mid-December at about 5000' on the east side of the Rocky Mountains. Often we have mild temperatures this late in the year but this year is unusually warm. We have had several snowstorms and some really cold days, but for most of the last two weeks its been below freezing overnight and as high as 60 F by day.

Plants are flowering.

Botanist Visiting London--in December

Two years ago I was in London in the first half of December. Looking back at the photos, I'm struck by the contrast to Colorado at the same time of year.

London, December

northern Colorado, December

London is well north of Denver, any map will show you that. Yet, the ocean effects prevail: it was much warmer than the Colorado we'd left behind. Not only was it warmer, I saw many plants that we cannot grow in Colorado.