google到下面一段话,可见其超强生命力:
Clover has a symbiotic relationship with lawns which are not fertilize, because clover is one of the few plants which can "fix" (produce) nitrogen from the atmosphere. Other plants can not do this and require nitrogen fertilizer to be added. Therefore, having clover in a lawn can help an unfertilized lawn.
Some weeds are acceptable, like clover. Clover grows vigorously in the hot dry weather of mid summer shading the soil, and fixes atmospheric Nitrogen, which the grass can use.
White Dutch clover is an early summer blooming, low broadleaf plant 7-8 cm (3") that is used in lawns. Until the 1980's it was included in grass seed mixes. Clover fixes Nitrogen enhancing grass growth. It needs no mowing, though tolerates it, and withstands traffic. Clover has deep roots so it is drought tolerant. Clover leaves die with frost leaving the soil exposed in the early spring and fall (coincidentally when grass grows vigorously), for this reason clover cannot be grown alone for erosion control. Clover spreads easily.