Alders Fix Nitrogen

Smooth alder or hazel alder (Alnus serrulata)
Photos by Georgia Native Plant Society

Hazel alder or smooth alder (Alnus serrulata) is blooming now with its showy yellow catkins. The woody female flower heads look like little pine cones. It's a tall multi-stemmed shrub to small tree in the birch family (Betulaceae).

This alder is native to freshwater and brackish water wetlands from Texas to Maine and into North Florida. It plays an important role in these wetlands because it fixes nitrogen in its root nodules using Frankia, a genus of anaerobic, filamentous bacteria in the Actinomycetes order. 

When soil is wet all or most of the time it is anaerobic (without air) and in these conditions, the normal soil microbes cannot survive and most plants cannot obtain enough nutrients from this soil. The alders' symbiotic relationship with this weird bacteria provides the nutrients they need to survive and they do so without much competition from other plants.

Florida Betony

Florida betony develops ridged tubers that
look sorta like a rattlesnake tail and are edible.

Florida betony (Stachys floridana) is an aggressive perennial wildflower. Most botanists think that it was originally endemic to Florida, but now has spread to most of the Southeastern states from Virginia to Texas. It's a member of the mint family (Lamiaceae) and has the typical square stems and opposite leaves along the stems. The beautiful bilateral flowers range from whitish to purple arranged on a spike. It does best in damp soils.

The tubers are edible

It's also known rattlesnake weed because of its rattle-like tuber. Florida betony tubers are edible when harvested in the spring when they are firm and white, but only if the area has not been poisoned with lawn-care chemicals. They have the crispness of a water chestnut with a taste reminiscent of a very mild radish. Most people don't eat them later in the season when they turn tan or yellow and are not as crisp.