An ocotillo bloom just off the side of the Brown Mountain trail. Photo by Chris Richards, Arizona Daily Star / 3/23/99
Q: I feel like my ocotillos are blooming earlier this year and I wonder if I am imagining it. Is there a trend for this in the Tucson area?
A: There are some groups such as the National Phenology Network (usanpn.org) keeping track of such things as blooming times and other phenological events for a wide variety of plants and animals. The data they collect via the citizen- and professional-science program Nature’s Notebook (naturesnotebook.org) is an important research tool for those studying climate changes on a regional and national level.
That said, you are really the best judge for your particular plants. The reason for this is that we have microclimates, and there can even be slight differences in temperatures that affect plant growth within neighborhoods.
For example, people who live near a wash tend to experience colder temperatures because cold air runs downhill. If you’d like to get involved in a science experiment, you can keep track of the blooming of your plants and other changes such as leafing out, producing fruit, and dropping seeds.
Data like this is valuable for showing changes in seasonal temperatures locally and globally. Once you get in the habit of keeping data on specific plants year round, you will have valuable information that can help you decide what’s changing and what’s just a feeling that may be incorrect.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions and requests for site visits may be emailed to
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