Exacum–commonly called Persian violet–is an evergreen subtropical perennial usually grown as an annual. Exacum bears violet to blue, occasionally pink or white flowers with conspicuous yellow stamens. Flowers appear on 4-angled stems above lance-shaped mid-green leaves.
Exacum can be grown as summer-flowering annuals in beds and borders in subtropical regions. It is grown as a houseplant in temperate regions.
Exacum needs well-drained soil. It grows well in full sun outdoors. It needs full light indoors.
Exacum is a genus of about 25 species of annuals and perennials native to stream banks from Yemen to India. One species, Exacum affine, is commonly grown in gardens and as a houseplant.
Get to Know Exacum
- Plant type: Tropical annual, short-lived perennial
- Growing zones and range: Zones 11-12
- Hardiness: Tender
- Height and width: 9 to 12 inches (23-30cm) tall
- Foliage: Leaves are light green, oval, waxy to 1 inch long
- Flowers: Small fragrant, star-shaped flowers are white, blue, or lravender with yellow eyes and stamens.
- Bloom time: Fall and winter
- Uses: Bed and borders in tropical regions, houseplant
- Common name: Persian violet
- Botanical name: Exacum
- Family name: Gentianaceae
- Origin: Near streams from Yemen to India
Where to Plant Exacum
- Light outdoors: Outdoors grow Exacum in full sun.
- Light indoors: Grow Exacum in full light.
- Soil outdoors: Plant Exacum in moderately fertile, welld-drained soil.
- Soil indoors: Grow in a soil-based potting mix with added sharp sand.
When to Plant Exacum
- Sow seed outdoors in early spring.
Planting and Spacing Exacum
- Space Exacum 9 to 12 inches (23-30cm apart.
How to Water and Feed Exacum
- Water Exacum freely during the growing season; water sparingly in winter.
- Fertilize Exacum with a balance liquid fertilizer every 2 to 3 weeks.
- To extend Exacum’s blooming period, remove the flowers as they fade.
- After the plant has finished flowering, it will die and can be discarded.
Growing Exacum as a Houseplant
- Grow Exacum in a warm room with bright light and high humidity.
- Use an extra rich growing medium and keep it evenly moist at all times.
- Fertilize exacum every two week.
Pests and Diseases
- Exacum is not prone to attack by insects.
- Exacum can suffer from botrytis blight, neucrotic spot birus, canker, and root rot.
- Propagate Exacum from seed sown in the spring for fall and winter bloom, or from stem cuttings taken before the plant is discarded.
Exacum Varieties to Grow
- Exacum affine, Persian violet. Grows 9 to 12 inches tall and wide; 4-angled stems and ovate to elliptic shiny leaves; bears scneted, lavender-blue, rose-pink, or white flowers with conspicuous yellow stames. Cultivars include: ‘Blue Gem’ compact to 8 inches tall with lavender-blue flowers, ‘Blue Midget’ to 5 inches tall with lavender-blue flowers; ‘White Midget’ to 5 inches tall with white flowers.