Crabgrass is a common type of weed that often invades lawns and gardens. It thrives in warm weather and can quickly spread, forming dense patches that compete with desirable plants for nutrients, water, and sunlight. This annual plant typically germinates in spring and can grow up to 3 feet tall, producing small, finger-like seed heads. Controlling crabgrass can be challenging, but methods include regular mowing, proper lawn care, and the use of pre-emergent herbicides. Maintaining a healthy lawn with adequate watering and fertilization can also help prevent its growth, allowing desirable grasses to flourish instead.