Originating from Western Asia and Southern Europe, the chaste tree (Vitex agnus-castus) is a low-maintenance, flowering tree that grows 15- to 25-feet tall and 15- to 20-feet wide at maturity. The chaste tree blooms with 6- to 12-inch lavender-blue spiked flowers and has slightly fragrant, grayish-green leaves that resemble marijuana leaves. The chaste tree grows best in USDA Zones 6 through 10, meaning that it’s hardy down to about -5 degrees Fahrenheit. This tree is drought-resistant and free of most pests or diseases.
Plant your chaste tree in location that receives full sunlight. Ensure that the soil is well-draining. Loosen the soil well at the planting site and amend the soil with coarse sand if needed.
Water your chaste tree only during prolonged dry periods or droughts. You can, however, water your chaste tree more frequently during the first and second years of growth.
Feed your chaste tree in early to mid-spring and again in early summer with a half dosage of a well-balanced fertilizer, such as a 10-10-10 NPK (Nitrogen-Phosphorous-Potassium). Follow the application instructions on the label.
Fertilizing is optional, but it will help to speed the tree’s growth.
Prune your chaste tree to control its size during winter only, because the tree’s flowers bloom on new growth. Prune back any dead, diseased or damaged branches and thin out branches by cutting them back to the trunk.
Spread a 2-inch layer of bark mulch around the base of the tree during its first and second years of growth. You may also want to spread mulch around the tree to insulate the root system during particularly cold winters.