Exacum affine, or Persian Violet, is a small herbaceous biennial plant. Leaves are dark green, ovate to 1 to 5 inches long. Plants with great age will reach 2 foot 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 bluish-lilac star-shaped flowers with deep yellow stamens are mildly fragrant. They are very showy.