It is a perennial evergreen herbaceous native of the Island of Socotra; to the genus exacum belong about 40 species of herbaceous plants, annual and perennial, but only E. affine is cultivated as an ornamental plant. It is a small plant, at most 25-35 cm high, with a roundish, very ramified habit; the stems are thin, herbaceous, tender, they bear numerous small oval leaves, light green, slightly fleshy. From spring to autumn they produce small flattened flowers, with five petals, purple or lilac, with striking golden stamens in the center; there are varieties with white or dark purple flowers. To encourage better flowering it is advisable to remove the withered flowers periodically.
In nature i Exacum similar prefer sunny or semi-shady positions; commercially available plants are usually grown in non-sunny greenhouses, therefore it is advisable to keep the plants in a very bright place, but not directly exposed to sunlight; if you intend to bring the plant outdoors and expose it to the sun it is advisable to do it gradually.
These small perennials are grown as houseplants, or even as annual garden plants, as a border or as terrace plants. To promote spring flowering it is advisable to conserve the plants, during the winter period, in a not too heated place, with temperatures close to 12-15 ° C.
As far as the supply of water is concerned, throughout the year it is watered with great regularity, avoiding letting the soil excessively dry but also creating stagnant water that is not healthy for this type of plants; during the winter months the waterings of the Exacum affine will be scarce and quite spaced in time, with the arrival of the beautiful season we intensify the watering, in order to avoid long periods of drought.
From March to October, add fertilizer for flowering plants to the water. For a correct development of the plant it is good to periodically proceed with the vaporization of the foliage in order to guarantee the right degree of environmental humidity.
These plants need quite rich but well-drained soils; you can use balanced universal soil, mixed with a good amount of sand. Generally they do not need containers that are too large, also because they are unlikely to survive very long; in general the exacum affine plants are cultivated only for 2-3 years in a row, so they propagate to obtain new plants.
The reproduction of this genus of plants takes place by seed; they can be sown in spring, to get a first flowering in early summer. It is also possible to sow the related exacum towards the end of summer, the young plants are kept in a tempered greenhouse, in this way the first flowering will take place at the end of winter.
Exacum affine: Pests and diseases
An excessively wet soil with stagnant water can favor the development of radical rot that must be counteracted quickly and effectively, to avoid serious consequences. An excessively dry or poorly ventilated climate can be conducive to the spread of mites on the underside of the leaves. In this case, numerous specific products are available to be sprayed on the plant to eliminate its presence.