Sunday, December 17, 2017

Flowers of the Colorado Winter

pansies, December 16, 2017 Northern Colorado
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.

The pansies (Viola tricolor)--first photo--are hanging on. But I also found periwinkle (Vinca minor) in bloom

periwinkle, December 16, 2017 Northern Colorado
periwinkle, Vinca, Dec. 16
Henbit (Lamium amplexicaule), a minor weed from Europe, was flowering. It is usually one of the first plants to bloom in the spring, especially in this open, rocky southeast-facing spot.

henbit, December 16, 2017 Northern Colorado
henbit, Dec. 16
If those don't convince you its mild, here is the postman, Rick, wearing shorts in mid-December
Shorts, December 16, 2017 northern Colorado
Rick, Dec. 16
As noted, photos above are from Dec. 16, 2017

It is worth thinking about the consequences of warm Decembers. You can describe these plants as fooled by the temperatures or as risk-takers.

I saw dandelion (Taraxacum officinale) seed pods that must have developed since last week's snowstorm. (I think the 2" of snow would have crushed them). This is successful risk-taking. Warm weather in winter is a temptation to plants. If they put up leaves or flowers they might make a net energy capture--more carbohydrate gained than were consumed to build the leaf--or produce a few more seeds. Conversely, a frost could destroy half-built leaves or unripe seeds, wasting all the investment. The dandelion below gambled that warm weather would hold long enough for its seeds to mature--and it did. Part of dandelions' success all over the world is being able to make asexual seeds (no partner needed, see earlier post) and rapidly ripen them.

dandelion with seeds, December 16, 2017 Northern Colorado
dandelion with seeds, Dec. 16
Most plants are not as good opportunists as dandelions.

When I went flower-hunting on November 24, 2017  in addition to pansies, periwinkle and henbit, I found dandelions open, an iceplant (Delosperma, likely D. cooperi) flowering, crane's bill (Eriodium cicutarium) (see earlier blog) in bloom, the snapdragons (Antirrhinum sp.) along my neighbor's driveway hanging on, calendulas (Calenula officinale) (see blog) and catmint (Nepeta x fassennii) flowering. Impressive diversity for a period I consider winter.

dandelion flowering November 24, 2017, northern Colorado
dandelion, Nov. 24
None of the plants I saw flowering in November-December are native to northern Colorado, however. I suppose that is partly because we don't grow many natives. On the other hand, my particular yard has dozens of them. That suggests that the cues that induce growth and flowering in nonnatives are different from those of natives. The chief one is probably day length. Our very short days are characteristic of mid-winter, with lots more cold weather to come. We have spring temperatures but winter day length. The natives, descended from plants that lived to create seeds in this region, use the reliable signal of day length to initiate growth. If they had these temperatures and twelve hours daylight, they might start to grow. Mild temperatures and nine hours daylight: those ancestors that stayed inactive lived, those that grew had their new growth killed by the next storm, and if they survived, entered the real growing season much weakened.

iceplant, Delosperma, flowering, Loveland, Colorado, Nov. 24, 201
Iceplant, Delosperma, Nov. 24
As you go south from the Temperate Zone toward the Subtropics, you come to places where sometimes the whole winter is very mild and in those years the opportunistic plants get a big head start on those that waited for the right daylength or really warm temperatures. I think northern Colorado is a long way from that spot and winter will put all the plants into deep freeze several times yet before real spring.
crane's bill flowering November 24, 2017 northern Colorado
crane's bill, Erodium Nov. 24
How warming temperatures (high in the Rockies plants are flowering on the average 10 days earlier than in 1974 (link)) or light pollution will affect northern Colorado plants, native and introduced, is one of the challenges of the future. Plants that wait for long days in a climate that that has warmed significantly will be at a disadvantage compared plants that are more responsive to changing conditions. In Colorado inflexible plants might be able to survive at higher elevations, where the temperatures match their cues for growth, but that's not an option most plants have. And we have made migration difficult by setting paved roads and suburban developments between plants and higher elevation habitats.
snapdragon flowering, Nov. 24, 2017 Loveland Colorado
snapdragon Nov. 24
The second major change in the environment is light. People love lighting the night: it makes it much safer. I was struck reading The Ties That Bound, Barbara Hanawalt's study of coroner's records in the Middle Ages, how often people out in the night died--got lost close to home in winter, fell into a canal in the dark, for example. Light makes lots of sense for safety. But it also means the daylength cues that plants (and animals) counted on are confused or obliterated. It is hard to predict how plants will respond, because lighting the night the way we like to do is something unprecedented in earth's history.
calendula flowering November 24, 2017 northern Colorado
calendula, Nov. 24
What I expect is that some species will adapt, growing and reproducing effectively under changed and changing conditions. However, probably some plants will not to respond or respond inappropriately. Those will decline in numbers. It would be great to identify those, as soon as possible. Partly because I don't want them to go extinct but also to learn from them. Plant genetics is reaching the stage that it can analyse the genes responsible for complex responses to determine what prevents these species from adapting to our changing environment. And that is very much worth doing because if I project 100 or 200 years into the future, I only see humans modifying the environment more and in ways I can't predict today.

Catmint, late summer; it looked a whole lot shaggier than this on Nov. 24.
I picked a bouquet and forgot a picture.
It has not regrown much since the snowstorm.
Thus, in an era where the internet lets us link everyone's observations, notice patterns around you. Take photos of how the forest or the riverbank looked in 2017, or of the backyard every January 1 or March 15th, making a record to compare. Or write down the date each year you see the first crocus or robin. Maybe you won't notice change in ten years, probably you will.

Or, like me, go flower-hunting with your camera on days when its a delight to find a flower.

Make a changing world a source of surprise and discovery.

pansies, Nov. 24, 2017, Larimer County, CO
pansies, Nov. 24
Comments and corrections welcome.

Note: With this post, I can now say "flowers bloom every month of the year in Loveland Colorado."

Of course, that's not every month in every year. And there's a big gap from Dec. 17 to Jan. 28 during which I haven't seen a flower, but this project is only five years old.

What about where you are?

CaraDonna, P. J., A. M. Iler and D. W. Inouye. 2014. Shifts in flowering phenology reshape a subalpine community. Proceedings of the National Academy of Sciences, U.S. A. 111 (13):
Hanawalt, B. The Ties That Bound, Oxford University Press.

Kathy Keeler, A Wandering Botanist

You might like this related posts:
Late Season Flowers link


January flowers link

 crane's bill

Snowdrops, a February flower  link 


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