Exacum affine, or Persian Violet, is a small herbaceous biennial plant native to the Island of Socotra, a Yemen archipelago in the Indian Ocean. Leaves are dark green, ovate to 1½ inches (4 cm) long. Plants with great age will reach 2 foot (60 cm) tall. They make a great houseplant and in USDA zone 7 they are used in landscaping as annuals.
Blooming Time: Seeds of the plant sown in mid-winter will bloom in the summer, and seeds sown in the fall will bloom in the spring. The small ½ inch (1 cm) bluish-lilac star-shaped flowers with deep yellow stamens are mildly fragrant. They are very showy.
Culture: Exacum affine need partial shade and a rich, well-drained soil mix. In the greenhouse, we use a soil mix consisting of 2 parts peat moss to 1 part loam to 1 part sand or perlite. Once seedlings become big enough to handle (the first set of true leaves), they are transplanted into 4-inch (10 cm) pots. Once they are transplanted, plants are given ample water and fertilized every other week until they set flower buds. At this time, plants are transplanted to 6-inch pots or hanging baskets -- usually 5 plants per 8 inch (21 cm) basket. Plants will bloom freely from this point on. During the winter months, plants are grown on the drier side and fertilizer is withheld until new growth starts in spring.
Propagation: Exacum affine are propagated from cuttings or by seed. Cuttings are slow to root and therefore seed usually produces much better plants. Seeds germinate in 15-30 days at 70-75° F (21-24° C).
Exacum affine was featured as Plant of the Week March 12-18, 2004.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.