Redbud (Cercis canadensis). It isn’t surprising at all to find that the Redbud is in the legume family (Fabaceae). Those seedpods certainly look like they belong in the family that includes beans, peas, lentils, and soybeans.

Something that immediately pops into my mind when I hear “legume” is that it is nitrogen fixer. Nearly 80% of the Earth’s atmosphere is nitrogen gas. Nitrogen is necessary for plants and animals to live and yet the nitrogen in the atmosphere is not in a form in which it can be used. Nitrogen gas must go through a process called nitrogen fixation. Fixation converts nitrogen in the atmosphere into a form that plants can absorb through their root systems.

Nitrogen fixing is a process that involves bacteria in the soil converting nitrogen gas into a form that plants and animals can use. It occurs in the root nodules of the legume.

However, with all that said, the Redbud is an exception. The Redbud does not have those root nodules that are usually found in legumes. The Redbud is not a nitrogen fixer. While it’s not a surprise to find that the Redbud is in the legume family it is a surprise to find it is not a nitrogen fixer.