Arisaema are available to buy from several nurseries. However, if you want the best chance of obtaining healthy plants, there are a few things that are worth knowing before parting with your hard-earned cash:
Most Arisaema are sold in the form of a dormant tuber during their resting period. The reasons for this are obvious, especially if they are being sold mail order or through an online webstore: mainly that the tubers can be easily posted out without damage and potted up and grown at home. An Arisaema plant in full growth is fragile and they don’t travel well.
Before buying, it is well worth asking where the tubers originated from. A reputable nursery will be able to tell you. The best source are nurseries that grow their own tubers. I would recommend avoiding purchasing tubers that have been imported, as these generally do not do well. For more information about the hazards of buying imported tubers, please read on…
Nearly all of the Himalayan Arisaema species that are sold in the UK originate from the same Indian nursery, no matter which retail outlet they are bought from. These tubers are grown and shipped en-mass either direct to nurseries, or through various import companies, on to wholesalers and then finally on to retail outlets. This takes an inevitable toll on the tubers. Although they may have originally been grown well, being piled into boxes and bounced around the globe causes bruising and damage. It is important to note that an Arisaema tuber is not like a true bulb with scales (eg, a Narcissus). The tuber is made of solid tissue, therefore, any bruising can spread through the whole tuber, rather than an individual scale. Such bruising will not always be obvious when a tuber is purchased, and they may still grow and even flower, even though the tuber is rotting away below soil level. People then wonder why they never see them again the following year and give up on the genus, quickly declaring them to be fussy plants.
Sometimes the bruising is obvious. Any soft or slimy patches are clearly going to be a concern. The closer that damage occurs to the apical shoot, the more likely it is that problems will occur. Similarly, if the apical shoot has been crushed downwards into the tuber, then this is likely to kill the tuber. Occasionally in such circumstances, dormant offsets around the main shoot may survive such damage.
Imported tubers are easy to tell apart from home grown ones:
Tubers are often covered with a yellowish anti-fungal powder. This is a requirement of the import / export process.
Tubers will look very ‘dry’ compared to a fresher home grown tuber.
If you do happen to buy an imported tuber, one nifty trick is to soak the tuber in water for 24 hours. The bruised areas absorb the water and turn a darker colour and can then be more easily spotted, which then gives you at least half a chance to deal with the problem before planting. Try and cut the damaged tuber away to firm healthy tissue and treat with an appropriate anti-fungal treatment before allowing to dry and callous over.
If you have the patience, growing from seed or offsets is very rewarding and an excellent way to produce healthy plants.
Finally, another reason to try and source home grown tubers is that these are much more likely to be correctly ID’d. Imported tubers are notorious for being wrongly labelled. If a nursery has grown the plants themselves, it stands to reason that they will have it named correctly!