Chastetree, also known as Vitex agnus castus or chasteberry, is a genus of flowering perennials native to eastern Europe. They can grow up to 18 feet tall and produce blue and white flowers in midsummer. The flowers have an aromatic fragrance that attracts bees, butterflies and hummingbirds. The chasteberry tree is easy to grow in most temperate climates and requires only routine maintenance to thrive in the home garden. The plant is also known by the names monk's pepper and Indian spice.
Plant chastetree in spring in a location that receives full sunlight. Spread 1 inch of organic compost over the planting site, and use a garden tiller to incorporate it into the soil to increase fertility and drainage.
Dig a hole three times as wide as the root ball and of equal depth. Remove the chasteberry tree plant from the container and place the root ball directly into the hole. Refill with soil and water immediately after planting to collapse air pockets in the soil.
Water chastetree three times per week during the first month of growth. Reduce the frequency to twice per week after the plant has become established. Keep the soil consistently moist at all times to prevent drought stress.
Feed chastetree plants in March, May and July during the first two years of growth using a balanced 10-10-10 fertilizer. Apply at a rate of 1 tablespoon per foot of plant height. Reduce fertilization to once in April and once again in June for the remainder of the plant's life.
Cut the chasteberry back to a height of 1 foot in late winter, just before spring growth begins. Trimming will remove portions of the plant that were damaged during the cold weather and prepare for new growth. Chasteberry only flowers on new growth; the cutback will not reduce the amount of blossoms.