Red Clover (Trifolium pratense) is an herbaceous perennial or short-lived biennial valued in agriculture and traditional medicine. It is easily identified by its characteristic rose-pink to purplish flower heads and leaves marked with a pale chevron pattern. Used as a high-quality forage crop for livestock, red clover also improves soil by fixing atmospheric nitrogen. The plant’s dense flower clusters provide essential nectar and pollen for various insects, particularly long-tongued bumblebees.
Typical Bloom Schedule
The initial flowering period for an established stand of medium red clover begins in late spring, generally starting between late May and early July in temperate regions. This timing can earn it the nickname “June clover.” The plant initiates growth from the crown in the spring, and the onset of blooming is signaled by the development of flowering stems that rise above the basal leaves.
Before the flower heads open, the plant reaches a height of 18 to 30 inches, depending on the cultivar. For agricultural purposes, the first harvest cut for hay is often timed when the stand is between one-quarter and one-half in bloom. This harvest window achieves the peak balance of forage quality and yield. The first flush of flowers is typically the most profuse and dense of the entire growing season.
Variables Influencing Bloom Onset
The exact timing of the first bloom varies significantly based on environmental conditions and the specific type of clover planted. Local climate and latitude are major influences, with plants in warmer, southern regions beginning to flower earlier than those in cooler, northern climates. Plant maturity is another strong factor, particularly the distinction between the two main types.
Medium red clover, also known as the double-cut type, is an early-flowering variety that produces many blooms even in its first year of establishment. In contrast, mammoth red clover, or single-cut type, is a late-flowering variety that typically does not produce flowers in the first year of planting. Mammoth types are often favored in regions with a naturally shorter growing season.
Management practices, especially mowing, are the most significant influence on subsequent bloom timing. A first cutting for hay, ideally taken no later than 15 days after the first heads appear, physically removes the current flowering stems. This forces the plant to divert energy into new basal growth, delaying the next flowering cycle. This intervention maximizes forage yield and manages the timing of subsequent blooms.
Bloom Duration and Subsequent Cycles
The flowering period of an individual red clover flower head is relatively short; the unpollinated cluster of florets remains receptive for pollination for up to 10 days. However, the overall bloom period for a field is prolonged due to the plant’s capacity for continuous, or indeterminate, flowering. A stand of medium red clover is capable of producing multiple flushes of blooms throughout the summer and into early fall.
After the first cutting or natural senescence of the initial flowers, the plant regrows to produce a second, and sometimes a third, flush of blooms. The second bloom often occurs approximately four to six weeks following the first harvest. This cycle continues as long as growing conditions remain favorable. These subsequent flowering events are generally less dense than the initial bloom.
The entire flowering season can extend from late spring through September until the first hard frost arrives. This long, multi-cycle bloom is beneficial for pollinator communities. By offering a continuous source of nectar and pollen late into the season, red clover supports long-tongued bumblebees and other insects when many other forage sources have faded.