The chaste tree (Vitex agnus-castus) grows as a small tree or shrub. It attains a height of 10 to 20 feet. Often referred to as the sage tree for its aromatic foliage, the chaste tree also produces fragrant purple, lavender, blue or white flower-spikes throughout the summer months that attract hummingbirds and bees. The tree has also been called the "hemp tree" because its foliage resembles the leaves of the marijuana plant. Small fruit follow flowering. Each fruit contains tiny seeds often used as a culinary seasoning. The tree grows easily in United States Department of Agriculture (USDA) zones 7B to 11.
Plant the chaste tree in full sunlight. The tree will tolerate partial shade, but the flower production is often reduced. Plant the chaste tree in the early spring to give it ample time to establish itself before winter.
Choose a location that offers well-draining soil conditions. The tree does not tolerate soil with high organic content that is overly moist. It will tolerate mild salt and can easily be planted near coastlines.
Dig a hole twice as large as the chaste tree's root system. Plant the tree at the same soil level it was planted at in the nursery. Tamp the soil down around the tree to remove all air pockets.
Apply 2 to 3 inches of mulch, such as peat moss or bark chips, around the base of the chaste tree. The mulch will help limit weed growth and help the soil retain water in the heat of summer.
Water chaste trees deeply once per week when establishing. In the winter months, reduce watering to once every three to four weeks.
Fertilize the chaste tree using a granulated 12-6-6 fertilizer in the late winter and fall after flowering has ceased. Water the fertilizer into the soil deeply.