Fortunately, Arisaema are not subject to many disease or insect problems. There is one disease, however, that you need to know about. Native populations of A. triphyllum are sometimes infected with a rust fungus, Uromyces ari-triphylli that shows up as orange spots on the undersides of the leaves, eventually covering the spathe and stem. There is no known cure for this. I have removed affected parts (to the trash - wash your hands afterward before touching any other plants) in hopes that the tuber would have enough reserves to return. Sometimes it does and is free of rust; sometimes not. But the recommended treatment is to discard the entire plant in the trash (not the compost), tuber and all, to prevent the fungus from spreading to other populations of any Arisaema species in the area.
Arisaema sikokianum
Arisaema sikokianum (Section Pedatisecta) is, perhaps, the one coveted by most gardeners for the pristine spadix made all the more prominent in contrast to the dark outer spathe. Hailing from Japan, it has been cultivated for many years.
It is also one of the pickiest I've grown regarding soil, absolutely requiring very sharp drainage, especially in winter, while dormant. The tuber will rot in cold, wet soil. It also seems to be fairly short-lived. The one pictured thrived for five years or so before simply vanishing one year. Gusman recommends a raised peat bed with leafy, sandy soil and sharp drainage.
An extremely early riser (early April for me), it is also subject to getting nipped by late frosts. You need to keep a large pot or cardboard box handy to cover the emerging growing tip when frost threatens.
It has an annoying habit, much discussed on the lists, of facing away from paved paths. Some opine that this is a reaction to reflected light; others note that even if dug and turned, the inflorescence will turn back. The truth is that nobody knows exactly why this happens, but it does - so be prepared.
Even with these faults, I would hate to be without this plant; it is so exquisite.
The variegated leaf form (grown from AEG seed) is even more stunning than the straight species. Cultivars with striped or spotted leaves are prized in Japan, but I've not heard of them being available in the US. The inflorescence is identical to the plain green leaf form.
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