To this genus belong about 150 species of rhizomatous perennial plants, originating in Central and North America and Asia; these are plants that produce erect stems, which bear large leaves, generally divided into 3-7 small oval leaflets, the stems can reach various heights, depending on the species, from 30 to 90 cm. The flowers bloom in late spring or in summer; these are very particular inflorescences, consisting of a long greenish spadix, almost completely wrapped in a spate of varied color, from green to purple, often streaked. They are very similar to the calla lilies; after flowering they follow small roundish fruits, of green, red or orange color, gathered around the stem as in a panicle. These very particular plants are dioecious, so to get the seeds it is necessary to have at least one female specimen and at least one male specimen; arisaema plants generally change sex with the passage of time: the young specimens are male, while the older and more robust specimens are female.
In nature they develop in wooded places, therefore it is advisable to place them in a bright place, but not directly exposed to solar rays, especially during the hottest months of the year as they could damage the leaves. They do not fear the cold, and can withstand very harsh temperatures; in any case in places with very cold winters it is advisable to cover the ground with dry leaves or other mulching material.
The arisaemas are watered regularly from March to October, avoiding excesses and trying to dry the soil between one watering and another; in any case, these plants can easily withstand short periods of drought.
Arisaema species are cultivated in soil rich in organic, soft and very well drained matter. Peat can be used, mixed with little sand and a good quantity of leaf soil. They can also be grown in pots. In this case, however, it is not always so easy to grow them better because maintaining the chemical and physical balance of the soil is rather difficult. In addition, during the winter, our potted plants should be protected from intense cold and frost as they damage the tubers.
The multiplication of arisaemas occurs by dividing the tufts, or by removing from the main rhizome the small rhizomes that develop over the years.
Arisaema: Pests and diseases
In general, arisaema species are not attacked by pests or diseases; sometimes it can happen that the rust hits the leaves, causing showy orange spots. In this case, it is very difficult to eliminate it. It is necessary to deprive the plant of the entire vegetative part hoping that the tuber is not affected by this process and wait for the following year. If the plant is still infected, it should be burned. In any case, the attack of rust is a rare case and usually occurs when our plant is already weakened for other causes.