Vitex agnus-castus, commonly called chaste tree, is typically grown in warm winter climates as a vase-shaped, deciduous shrub (to 10-15' tall) or trained as a single trunk tree to 20' tall. In cold winter areas in USDA Zones 5-6, it is more often grown as a 3-5' tall herbaceous perennial. Features aromatic, compound, palmate, grayish-green leaves with 5-7 lance-shaped leaflets (each leaflet to 6" long) and tiny, fragrant, lavender to pale violet flowers appearing in loose panicles (to 12" long) in mid to late summer. Flowers are quite attractive to butterflies.
The seeds have a period of dormancy. They can be planted outdoors in the fall or winter for spring germination or they can be cold stratified to simulate winter conditions and to break their dormancy at any time of the year.
- Place the seeds in a plastic bag and seal it. Store the bag in a refrigerator for two months.
- Fill a pot with potting soil.
- Sow the seeds on the soil and cover them with a thin layer of soil.
- Water the container and leave it to drain.
- Put the pot in a warm, sunny area.
- Water the pot regularly so that the soil is moist but not wet. The seeds take 4-6 weeks to germinate, although some of the seeds may take longer than that to germinate.
- The seedlings can be transplanted when they are a few inches tall.