Characteristics of the white Lisianthus
The white Lisianthus, belonging to the botanical family of Gentianaceae and to the genus Eustoma, is an annual semirustic herbaceous plant, if cultivated outside for the cut flower trade, and perennial if kept in pots in the apartment, for ornamental purposes. Lisianthus is highly appreciated for its elegant and simple appearance and is widely used for wedding decorations, first communions and other celebrations. The plant is native to America, in particular from the Southern United States and Mexico, therefore countries with a warm climate. It has a slow growth and its stems are generally about 50 cm long, thin and flexible, covered with lance-shaped and waxy leaves of a bluish-green color. The white flowers are large and bloom at the tips of the stems. Lisianthus flowering occurs between spring and summer.
Positioning, climate and reproduction
Lisianthus loves the moderate climate, needs lots of light and fears intense cold and rain. However, direct sunlight should be avoided, partial shade should be preferred, the plant should not be kept near sources of heat and should not be exposed to drafts. The ideal growth temperature is between 18 and 22 degrees and never below 17. The multiplication of white Lisianthus occurs by seed or by division of the tufts. The sowing will be carried out in boxes in winter, towards the end of February, leaving the soil in a sheltered place, at a mild temperature, until the seeds are completely germinated. This type of reproduction ensures the best success, leading to a luxuriant flowering in the summer period. Instead, the division of the clumps is performed in spring by replanting the parts of the plant.
Soil, fertilizer and watering
The plant requires a loose soil, rich in organic substances, composed of 2 parts of earth, 1 of peat and 1 of sand, for a good drainage that avoids the water stagnation that causes the root rot. Fertilization is carried out in spring, every 20 days, using a fertilizer for flowering plants diluted in the water of the watering, following the manufacturer's instructions. Fertilizers that are poor in phosphorus and rich in trace elements such as iron are ideal. Lisianthus needs to be watered frequently but not excessively, particularly in spring and summer. It is necessary to supply water to the plant in order to always keep the soil slightly damp, preventing it from becoming too dry, being careful not to excessively wet the flowers. In the winter season the waterings will be occasional. It is advisable to vaporize demineralized water on the leaves.
Further tricks and diseases
The plant does not require a real pruning but only the trick to remove the withered flowers and the damaged parts. Lisianthus grown outside, as an annual plant, does not require repotting. When instead it is kept indoors, as a perennial plant, it is necessary to carry out the repotting every two or three years, using a slightly larger pot. In any case, the maximum diameter of the container will be 20 cm. The plant can be affected by various fungal diseases including white malaria, also called oidium, which manifest as white mold. Lisianthus is also subject to the dangerous attack of mites, such as red spider mites, cochineals and various aphids. Lepidoptera larvae also cause serious damage to the plant. Depending on the disease, specific fungicides and insecticides should be used.