In addition to grasses, certain non-grass plants are used to establish lawns, called complementary. The most commonly used plants that supplement a specific composition of grasses are: shamrock (Trifolium repens) and yarrow (Achillea millefolium).
White clover is added to poorly fertile soils, but sufficiently moist. Its advantages include: maintaining a vivid green color for a very long period, resistance to heavy trampling, resistance to periodic unfavorable weather conditions, resistance to low mowing. As a legume, it provides a good appearance for poorly fertilized lawns, which in such conditions is difficult to achieve with other grass plants. The disadvantages of white clover on sports lawns include slipperiness, which can sometimes be considered dangerous. This plant very often appears spontaneously on poorly tended lawns, and above all, insufficiently fertilized.