Tuesday, September 6, 2011

Arisaema Costatum

We all have plants we like, and we all have plants we hate. Let me introduce you to one that I happen to like - Arisaema Costatum. In fact, it's one of my favourites, and the more I think about it, the more I can see why! The single trifoliolate leaf (meaning each leaf has 3 leaflets) is large and glossy with attractive veining and it contrasts well with other leaf shapes and textures. The spathe is brightly coloured, and even though it is held beneath the leaves, it stands out and demands closer inspection .

Requiring minimal input from me, and proving hardy here even in my cold and heavy 'Devon Red' clay soil (surely another bonus!) it is always late to emerge after winter. The new shoots don't usually appear until mid / late June, just when you start to wonder if it is going to make a reappearance at all.
Leaf and spathe emerging from the papery cataphyll at the beginning of the season. I find the way Arisaema grow fascinating!
The spathes are just stunning, especially when admired closely. The white stripes and veins contrast brilliantly with the maroon background, and the spadix appendage trails away in a twisted and tortuous fashion, often ending up in a coiled bunch at the base of the plant.

Arisaema costatum spathe fully open. The spadix appendage is long and trails on the ground for some distance or gets caught up in the foliage.
The foliage on one or two of my plants is just starting to show the first sign of fading now, the sure sign that Autumn is approaching and the result of one or two cooler nights. As with all my Arisaemas, I try to keep them in leaf as long as possible. That way the corm gets maximim nutrition and help to bulk it up for the next season.

Some of my plants also have clusters of berries forming, small, hard and green at present, although they will ripen, swell and turn red later in the year. I'll sow the seed and bring on the next generation. Young plants have a distinctly different leaf shape - known as a hastate shape. Once into the 2nd or 3rd year, the leaves should take on the 'adult' shape and become more recognisable, and after 4 or 5 years, the corm should reach flowering size. So is that a long time to wait for a spathe from seed? Well, yes, I guess it is. But is is surely worth the wait!

Arisaema costatum, showing the hastate leaf shape of a young plant. This one has attractive red tints to the central veins and margins. Nice!