Planting Guide: How to plant, grow and care for your Arisarum
What is an Arisarum?
It is hardly surprising that the smaller, quietly coloured and relatively odourless species of Arisarum take second place behind the Arums.
This is a great pity since this small genus of three species has much to offer both the horticulturist and botanist.
Arisarums can become quite weedy if left to their own devices in a Mediterranean climate. However, the three species of Arisarum are in Australia, along with some interesting variations.
In the Southern Hemisphere Arisarum vulgare starts flowering in April and continues to flower until November. Arisarum simorrhinum starts flowering in June and will flower until July.
The third species, Arisarum proboscideum, flowers from August until November.
Arisarum species are easily grown either in wide pans under frost-free glass in the case of Arisarum. vulgare and Arisarum simorrhinum. Arisarum proboscideum prefers a shady position outdoors for In mild localities A. vulgare will be successfully planted at the base of a north or east facing wall.
Arisarum vulgare is usually sold, in the autumn, as dry-packed tubers in the northern hemisphere. In the southern hemisphere A. vulgare is sold as a potted plant. Dry-packed tubers should be planted as early as possible to enable the plants to form a good root-system before winter. Planting too late will result in weak plants and small sized tubers the next year.
Arisarum simorrhinum is sold in the same way as A. vulgare although rarely seen in cultivation in Australia. It has not proved to be as hardy as A. vulgare and definitely requires frost-free conditions.
The best way to buy A. proboscideum is as a growing plant. The tubers of this species are far more delicate than those of the other species, and suffer particularly badly if allowed to dry out. Pots of A.proboscideum are usually available from good garden centres in late spring.
Arisarum proboscideum does not grow well under glass, for the summer heat seriously weakens this woodland species. Outdoor cultivation in a shady but not too dark, fairly damp position is best. Before planting, the soil should be dug well and any perennial weeds removed. If the soil is particularly acidic, a sprinkling of lime, about 50g to the square metre, is beneficial. Once established, A. proboscideum should not be disturbed unless the colonies become too large or congested. If replanting becomes necessary it should be done in the spring. Arisarum proboscideum does not grow well under glass, for the summer heat seriously weakens this woodland species. Outdoor cultivation in a shady but not too dark, fairly damp position is best.
Arisarum Growing conditions
Foliage is at its best in light shade, while the red berries are most spectacular with more sun. This plant thrives in moist conditions. Water during dry spells, and then reduce water when leaves begin to wither.
Fertilizer/Soil and pH:
Grow in soil rich in organic matter with a slightly alkaline to neutral pH (7.0 to 8.5). A balanced fertilizer can be applied monthly during active growth.
Arisarums seldom have disease or pest problems, and the foliage is resistant to damage by both slugs and deer. All parts of the plant are toxic and animals do not tend to graze them.
The inflorescence is quite obvious in A. vulgare and A. simorrhinum. However you would only see the long tips of the inflorescence of A. proboscideum. The flowers are insignificant and are rarely seen. At flowering time the plant sends up a spathe and spadix (which carries the flowers). The spathe and spadix are obvious when compared to the leaves.
Divide clumps of tubers in summer when plants are dormant. It is rarely needed for Arisarum proboscideum to need to be divided.
Withering leaves may be removed in late spring and it is at this time that the tubers are left in the ground/pot for next year. The withering leaves will disappear of their own accord if left.
How to plant Arisarum?
Arisarums should be planted with a covering of 2-2cm of potting mix/soil. The tuber will pull itself down to where it wants to grow.
How to grow Arisarum?
Arisarums can be gross feeders and appreciate a highly fertile environment. At Elite Bulbs we fertilise every two or three weeks. They can be planted in any fertile place and let go. They will do alright in poor soils but excel when loved.
How to care for Arisarum?
Arisarums are low maintenance. No matter what the conditions as long as they are kept damp. By summer the tubers will have pulled themselves down far enough that they will survive. They are a plant that requires very little care.