Has Climate Change Affected Flowers?

By Chick Keller
November 2009

Many recent studies show that formerly southern birds, butterflies, etc., are moving north, and people are able to plant crops farther north. White Rock now is home to a southern desert-dwelling bird, the curve-billed thrasher, and southern white-winged doves have invaded even the town site. All these effects are presumably due to global warming.

PEEC decided to see what effect, if any, recent warming is having on our native plants. One might suspect that such warming might stress them in some way, or conversely some species might thrive by producing extra seed. How could we find out? PEEC proposed a fairly simple study to determine what's happening. It assumes that, if the growing season is becoming longer, native plants might bloom longer into the fall and perhaps bloom earlier in the spring.

Our first test comes from a booklet I wrote back in 1989, "The Twelve Little Yellow Composites of Summer." In it I give the dates when twelve different species are in general bloom. For example, perky sue is in general bloom in early May. Since that booklet was written twenty years ago, it might already show these few plants blooming earlier. In fact, it does not. Furthermore, we know that for years pasque flowers could be found first around April 8, and this date doesn't seem to have changed much either. But these are only a few plants and we are only testing for early bloomers.

What are the other plants doing and are they blooming longer? To answer this question, PEEC has begun making lists of species blooming late in the year. In an early list made the first week of October 2006, I counted some 60 species still in bloom.

This year I decided to enlist the help of plant lovers and hikers around town to list species blooming the last week of October. With people on regular hikes or just looking around, we made a list of 46 species! Besides being the start of a small study, it was just plain fun trying to see what blooms were left. Some surprises were strawberry, lupine, and sand aster. Next year to make the study a bit more comprehensive (and to have more enjoyment) PEEC is planning three "Big Day" searches. Like similar birding events, on a particular day each year teams will go out looking for what's blooming. Someone knowledgeable will lead the search, but everyone contributes since more eyes find more blooms. At the end of the day we will gather at PEEC to make up the list and have a small party. We hope that over the years we might see trends in some plants as the climate warms. We'll also keep notes on whether the year was particularly warm or cool, wet or dry. Tentative dates for these "Big Days" are May 1, July 15, and October 1. Anyone can join the groups and all are welcome. There will be hikes down the Red Dot Trail and on the mesas in White Rock, as well as canyon and mountain meadow hikes and even some on townsite trails.

For the late hike we will be looking particularly for plants that continue blooming or might rebloom. Some just bloom once and die, but others such as perky sue and Wooten's groundsel bloom early and can be coaxed into blooming a second time if the weather continues warm. This year both were found in our count. Anyway it should be fun and, as the years pass, we might see more and more late bloomers. Come and join PEEC in this and its other citizen science activities.

For a list of the 46 late bloomers of October 2009, see What's Blooming Now.


Return to PEEC website Articles by Local Authors.