Common Mallow – From the Mallow Family. This weed can be both an annual and biennial weed. It will grow to be 1 to 3 feet tall. The weed grows from the base. It has large leaves that alternate and are round in shape. They have a red spot at the base of the leaf. The weed does have small flowers. The flowers are blue or pink. The plant spreads by seeding out. It can grow year round with water but will usually die in areas not watered. It can be prevented by a pre-emergent. Some selective herbicides and glyphosate will also control it.