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Arisaema - Cobra Lily - Arisaema sikokianum
Common Name(s): Cobra Lily, Jack in the Pulpit
Native to: Africa, Asia, North America
Watering: Drought tolerant
Planting Aspect: Full sun to part shade
DescriptionArisaema is a tuberous or rhizomatous perennial closely related to Arum, but is differentiated by the absence of sterile flowers on the spadix. Their ornamental bracts (known as the spathe) with its own unique shapes and colouring, make them particularly desirable in various garden settings, however as the flowers are more unusual than beautiful, their greatest merit is in the colouring and shape of their foliage.
The foliage is variable and the plant often only has one or two leaves per shoot. The leaves are usually divided, sometimes very finely and make a frilled base to the erect flowering stem that emerges through the centre of the foliage. The flowering stem carries a single flower spike in spring or early summer. The bloom is a central spadix of minute, fleshy flowers surrounded by a coloured spathe. Heads of fleshy red fruit follow the flowers.
In their native habitat, most Arisaemas grow in humus rich soil on the forest floor and often in small isolated colonies, therefore particular consideration must be given when choosing the growing location and the conditions required. As they require regular moisture and shade, they will look their best planted alongside other shade loving foliage plants such as Hostas and ferns.
Hardiness of each cultivar varies, however most cultivated varieties can be grown where winter temperatures drop to below 0 and frost prevails provided the soil is not saturated, however tropical species must only be grown in frost free areas.
Try to grow the tubers where they will receive filtered sunlight, but definitely protect them from direct sunlight during the warmest part of the day. Normally the tubers should be planted in autumn or spring 7.5 to 10cm deep (however some experienced growers have planted them up to 30cm deep for winter protection in colder climates) and 25 to 30cm apart.
The soil must be high in organic matter and free draining. They can be grown in containers with a mixture of equal parts organically rich top soil, leaf mulch and sharp sand. If planted in spring, only water sparingly until the roots develop then slowly increase the amount of water and feed with a balanced organic fertilizer.
As soon as the flower stem appears, stop feeding but continue to give water over the growing season until the spathe has withered and the foliage starts to turn yellow. Reduce the watering while the foliage dies down and the plants end up being somewhat dry while they are dormant over the winterperiod.