Alfalfa (Medicago sativa) is a widely cultivated perennial leguminous plant, globally recognized for its significant role in agriculture. Often referred to as the “queen of forages,” it provides highly nutritious feed for livestock. While its green foliage is prominent, the small blooms of alfalfa are a significant and often overlooked aspect of its life cycle and overall value.
What Alfalfa Blooms Look Like
Alfalfa plants produce small, delicate flowers typically arranged in dense clusters called racemes. The most common flower color observed in alfalfa varieties is a light purple or violet hue. However, varieties can also display blooms in shades of blue, yellow, cream, or white, and some may even exhibit mixed or variegated colors. Each individual alfalfa flower consists of five petals, including a large standard petal, two wing petals, and two fused keel petals that enclose the reproductive organs.
When Alfalfa Blooms Appear
Alfalfa plants exhibit multiple bloom cycles throughout their growing season, particularly in regions with extended warm periods. The typical flowering period for alfalfa generally spans from June through August, and sometimes extends into September. After each harvest, the plant undergoes a regrowth phase, transitioning from vegetative stages to the development of new buds and subsequent blooms. Environmental factors, such as temperature and the timing of previous cuttings, significantly influence the speed and timing of these successive blooming periods.
Why Alfalfa Blooms Are Important
Alfalfa blooms are essential for the plant’s reproduction and the subsequent production of seeds. For successful pollination, the alfalfa flower must be “tripped,” a mechanism where the keel petals are pressed, releasing pollen. These flowers serve as a significant source of nectar and pollen, attracting a diverse array of pollinating insects. Alfalfa leafcutting bees are particularly effective pollinators, directly contributing to higher alfalfa seed yields. While honey bees also visit alfalfa for nectar, they are generally less efficient at tripping the flowers compared to other bee species.
Practical Significance of Alfalfa Blooms
Alfalfa blooms indicate plant maturity, guiding agricultural decisions. As blooming progresses, stem fiber increases, reducing protein and digestibility for livestock. For optimal hay quality, harvest occurs at the bud stage or when about 10% of plants are in bloom. Full bloom is reserved for seed production, maximizing seed set. Blooms also support vital pollinator populations, benefiting the broader agricultural ecosystem.
Managing Alfalfa Blooms
Managing alfalfa blooms involves strategic harvesting based on objectives. For high-quality hay, producers cut before extensive bloom, typically at the bud or early flower stage, to preserve nutritional value. To enhance stand persistence and root reserves, especially before winter, alfalfa may be allowed to reach full bloom at least once a year. For seed production, the crop is left to bloom fully, ensuring ample pollination and seed development. Multiple cutting cycles, often three to five annually, are timed to balance forage yield, quality, and plant health.