Trifolium dubium, commonly known as Lesser Trefoil or Suckling Clover, is an annual herb in the pea family Fabaceae, native to grassy areas in Europe and now introduced worldwide. It is often associated with the traditional Irish shamrock. This small plant typically grows to a height of 4-6 inches (10-15 cm) and spreads to form a low mat. Lesser Trefoil has small, yellow flowers that bloom from May to September, which are less showy compared to other clovers but still attract pollinators. The trifoliate leaves are a characteristic feature, and it is an allotetraploid, likely arising from the crossing of Trifolium campestre and T. micranthum.

Lesser Trefoil is valued for its use as a ground cover and for its nitrogen-fixing abilities, which can improve soil fertility. It is also used in lawns where it can tolerate close mowing and is sometimes planted in pastures for forage. In cultivation, it prefers full sun to part shade and thrives in a variety of soil types, provided they are well-drained. It requires moderate watering and is relatively low maintenance. However, it can become invasive outside its native range, so gardeners should check local regulations before planting. It is not typically affected by serious pests or diseases, but it can compete with other plants for space due to its spreading habit.CC BY-SA 4.0