Medicago sativa ( Alfalfa )
A perennial ( up to 20 years though usually less than half ) that is native to south-central Asia however is frequently planted as a cover crop and also naturalized in parts of central & eastern North America, western & central Europe. It can reach up to 3.3 feet in height though the roots often penetrate the soil at a depth from 7 to 10 feet and sometimes as much as 50 feet in dry climates on soil with groundwater beneath.
The leaves ( dried or fresh ) can be made into a mineral rich tea though not very strongly flavored and often mixed with mint.
The seeds are eaten by many birds. The flowers support bees.
Alfalfa prefers somewhat neutral, deep, well drained soil and is drought tolerant. In Alberta; it can be grown as far north as Rainbow Lake and Fort McMurray.
Propagation is easily done from seed soaked overnight and planted in moist soil.
The roots contain nodules that contain bacteria that fix nitrogen. An acre of Alfalfa may fix up to 200 or more pounds of nitrogen in a year. Alfalfa is often planted as a cover crop to improved depleted soils or also as a green manure. Being a perennial, it may be allowed to grow for a few years while it improved the soil while also providing hay and nectar which is valuable in honey production. Alfalfa leaves, either dried or fresh, can be used as a garden fertilizer as they contain abundant nitrogen as well as a growth stimulant called Triacontanol.
A related plant called Medicago lupulina ( Black Medick ) is also commonly found in North America. It can be grown in all of Alberta except the extreme north.
* photo taken on July 9 2022 in Bayfield, ON
