Shoal Creek Chastetree ( botanical name - Vitex agnus-castus 'Shoal Creek' ) is deciduous and grows to a mature size of 13 feet tall by 18 feet wide. This shrub enjoys partial shade and provides none fall color. The Chastetree flowers in spring to early summer with lavender blooms. It normally has a high drought tolerance and a fast growth rate when planted in zone 5b-8.