Black Cottonwood is a native tree that grows in northern  southern and central California. It is fast growing and moderately long-lived. It grows in an upright form to a height of 100 feet  with active growth during the spring and summer. Flowers are yellow and bloom in the mid spring. Leaves are medium green and deciduous. Black Cottonwood is a great choice to help build a natural irrigation system - its long shallow roots will reach out to the water source and pull underground water molecules through your garden. It needs moist soil until mature  and then becomes moderately drought tolerant. Great for birds and butterflies.