Though often thought of as yellow, yarrow blooms in a range of colors that include yellow, white, red, pink and orange. This hardy plant grows in USDA hardiness zones 4 through 8, but it can withstand cooler temperatures. Many homeowners grow yarrow as a ground cover. Its low need for water and its drought tolerance makes it a suitable lawn alternative. It is a low maintenance plant and when used as a lawn alternative it requires mowing only twice per growing season. It is a herbaceous perennial, meaning it dies back in the extreme cold, although it does prefer cooler climates to hot ones. The plant is also used widely in rain gardens where its fibrous root system filters water and improves drainage. Though the plant withstands temporary flooding and helps mitigate erosion, it shouldn't be placed in consistently wet soils. Yarrow grows naturally in open, sunny grassland and it does best when grown domestically under similar conditions. It prefers light, well-draining soils and is frequently used as a border plant. It pairs well with a variety of other plants and improves the quality of surrounding herbs. The plant is well-known for its scientifically proven medicinal qualities. Its high alkaloid content makes it deer tolerant. It also repels ants, flies and Japanese beetles but attracts butterflies, bees and other pollinators. The ground cover is slow-growing, but over time a substantial presence is maintained in the landscape. When left untrimmed or mowed, the plant reaches a diminutive height of up to 3 feet and a clumping spread of 1 foot. The flower extends from a tight rosette and the foliage can be bright to deep gray-green. The plant's pleasant aroma is one reason for its being recognized for medicinal qualities. A pungent plant, it is also used for decorations and craft purposes. The dried flowers retain their color and are frequently seen in wreaths or in baskets.