This is Berberis nevinii, also known as Nevins Barberry. This drought tolerant shrub likes to live in full sun where it can grow to about ten feet tall. The yellow blossoms are on display from late Winter until early Spring. This plant is on the federal and state endangered lists. Birds love the red berries produced by this bush and it is fairly deer resistant. USDA Hardiness Zones 5 to 10.