These plants shouldn't be grown in the garden during the cold period; in autumn the plants usually perish, and should be eradicated from the ground. Plant which need at least a few hours a day of solar light.These plants can be brought outside only if there isn't any more danger of freezings. Usually they are moved to the garden, or terrace, during the months of April-May.
Before placing the annuals, letís enrich the soil with a small dose of organic fertilizer or slow release granular chemical fertilizer; during the spring we should use a specific fertilizer for flowering plants to be mixed with the irrigating water, to be used every 20-30 days.
The Vervain has a panel-like development, therefore it tends to widen very much. These plants have a one or two year development. This plant in the spring, summer, autumn, winter assumes a red colouring; it is medium in size and can reach 20 cm high. It doesn't keep its leaves in the winter.
Letís avoid watering the The Vervain excessively, always leaving the soil dry for a few days between one watering and the other, therefore letís irrigate the substratum deeply every 1-2 weeks with 2-3 glasses of water . As the cold weather arrives, in autumn, we can interrupt watering, and let the plants perish.
As the day-time temperatures rise at the beginning of the spring, it is agreeable to practice a preventive treatment, with a wide-range insecticide, which should be applied when there arenít flowerings in the garden. Before the buds become too large, it is advisable to also treat them with a wide-range fungicide, to prevent the development of fungal diseases which spread easily when there is an elevated environmental moisture.
They prefer dissolved soils, with an optimal drainage.
The Vervain is scented; It can be grown in a vase when desired. The indications given in this article are related to a medium size plant.