Exacum affine aka Persian Violet

Exacum affine belongs to the gentian family, Gentianaceae. Gardeners know it as Persian violet or German violet. Other names include Arabian violet and Arabian gentian. It grows wild on Socotra and in southwestern Oman. Kew places it in desert or dry shrubland habitats. Gardens usually grow it as an annual or biennial. Some sources describe it as a short-lived perennial.

This small plant forms a dense, rounded clump. Garden plants often stand 0.5–1.5 feet (0.15–0.46 m) tall. RHS gives an upper height of 1.6 feet (0.5 m). Florida reports heights reaching 2 feet (0.61 m). Spread ranges from 0.5–1 foot (0.15–0.30 m). RHS allows a wider spread of 1.6 feet (0.5 m). Growth is slow, and green stems carry many small leaves. The glossy, dark green leaves have an oval shape. They grow in opposite or nearly opposite pairs. Their edges are smooth, and their surfaces lack hairs.

Fragrant flowers can cover much of the plant. Blue and deep purple are the main reported colors. RHS also records pink and white flowers. Each flower measures about 0.07 feet (0.02 m) across. Yellow stamens stand out against the petals. North Carolina and Florida report spring and summer bloom. Flowers can last over a long season with suitable care. Florida describes the fruit as lacking garden interest.

Most US sources favor partial shade and moist, well-drained soil. North Carolina warns against direct sun, while RHS recommends full sun. Rich potting soil suits plants grown in containers. Florida advises moderate watering and feeding. The plant tolerates several soil types when drainage is good. RHS lists acidic, neutral, and alkaline soils. Outdoor plants need warmth and protection from cold. Missouri and North Carolina place it in USDA zones 10–12. RHS rates it H1C for UK conditions. It suits beds, borders, edging, ground cover, and patio pots. Hanging baskets offer another use.

Keeping plants alive after flowering can be difficult. Growers can raise replacements from seed or cuttings. RHS advises cutting plants back once flowering ends. Most sources report few serious pest or disease problems. Florida notes gray mold on seeds and damage from broad mites. Other mites and worms may also cause trouble. ASPCA lists it as non-toxic to dogs, cats, and horses. The supplied sources do not establish any edible use.