There is some use of annual clovers in winter rainfall areas of California and Oregon, but most plantings of the commonly used annual clovers (arrowleaf clover, ball clover, berseem clover, crimson clover, rose clover, and subterranean clover) in the United States are made in the South (Figure 1). This is especially true with warm season grasses being grown on droughty soils. Thus, there are situations in which use of an annual clover with perennial grass is preferable. However, in many areas in the South, perennial clovers will not survive the heat and drought of summer, and first-year growth of a perennial clover is normally less than that of annual clovers.
In addition, the autumn forage growth of established perennial clovers is better than that of recently germinated annual clovers. The reason is that annual clovers, which must come from seed each year, have more difficulty becoming established due to competition from grasses and other plants (especially perennial plants) than do perennial clovers which already have a good root system established. In most situations in which clover is to be grown with a perennial grass, it is preferable to use a perennial clover (if adapted) rather than an annual clover. Thus, a stand of a perennial clover may contain recently established plants that are less than a year old as well as plants that are more than a year old. Perennial clovers also make seed, but (assuming environmental conditions and management are appropriate) individual plants can live more than one year. The percentage of hard seed produced varies depending mainly on the clover species and variety, but environmental conditions also have an influence. Delayed germination is due to “hard seed” which have a seed coat that must be broken down over time to allow water to enter the seed. In the case of many annual clovers, much of the seed produced in spring or early summer will germinate in the autumn of that year, but some may lie dormant until subsequent years. All annual plants present at any given time will die within a 12 month period. If a stand of an annual clover is present in an area for more than one year without being replanted, it is due either to reseeding or delayed germination of previously planted seed. Annual clovers reproduce only from seed and not by vegetative propagation from roots or other plant structures.
This publication provides general information regarding a number of points that should be considered when deciding which clovers to plant.Īnnual clovers complete their life cycles within one year (i.e., plants emerge from seed, grow, produce seed, and die, all within a 12 month period). Furthermore, clovers may also differ with regard to the particular benefits they provide (for example, if forage growth is desired at a specific time, one clover may be a much better choice than another).Ĭonsequently,when planting decisions are made it is important to have in mind the traits of various clovers and then take care to select the one(s) best suited to the situation. Some are more tolerant of certain climatic conditions, soil conditions, and/or management regimes than others. However,the characteristics of clover species differ. Benefits clovers can provide include improved forage quality, increased forage yield, biological nitrogen fixation, extension of the growing season, soil improvement, and land beautification.
Don Ball, Extension Agronomist/Alumni Professor (Auburn University) and Dr.Garry Lacefield, Extension Agronomist/Professor (University of Kentucky) on behalf of the Oregon Clover Commission, Salem, ORĬlovers are wonderful plants that can contribute greatly to forage/livestock programs,to soil stabilization, and in other situations in which plant vegetation is desired.