Quick answer: 6 native Colorado plants have a recorded bloom range that includes March.
6 species
- Bearberry Arctostaphylos uva-ursi · 16 states
- Boxelder Acer negundo · 14 states
- Eastern cottonwood Populus deltoides · 14 states
- Gambel oak Quercus gambelii · 6 states
- Gray alder Alnus incana · 12 states
- Quaking aspen Populus tremuloides · 24 states