Based on information from Dr. Wilbert Hetterscheid, the top Amorphophallus expert in the world, in Amorphophallus species the "corm" is the stem tissue which is encased in the small bud at the top of the tuber full of stored food. That bud grows upward into a divided leaf and outward into roots with the tuber beneath.

Although many authors use the terms bulb, corm and tuber interchangeably the only term that is truly applicable to an aroid is tuber. There was recent discussion on the International Aroid Society forum Aroid l regarding this subject and several botanists chimed in to agree the words bulb and corm should not be used.

The stem is the central axis of the plant, not the support of a leaf. The support of the divided leaf on an Amorphophallus and all aroids is called the petiole. The plant actually uses the food om the tuber during the summer and is virtually always smaller at the end of the season provided it is happy.

I have seen my Amorphophallus titanum tuber so tiny just after it goes dormant I thought it was about to die but the next year it has grown large again during dormancy.

A corm is an underground stem to which the above-ground parts of the plant may die back in the dormant season. It often stores starch and when it regrows foliage will come from the top and roots from the base like a typical stem but there are no true examples of a corm in the aroid family.

A tuber is a strongly condensed stem as well as an underground structure which is almost entirely a starch storage organ.

It wouldn't be unnatural for your tubers to be smaller at the end of the growing season since the plant has been using the stored food. Unless you live in an extremely cold climate Amorphophallus konjac can easily stay in the ground year round. I leave at least 40 tubers in the ground all the time in zone 6b and they reproduce themselves every year. I've traded mail with growers as far north as Philadelphia that do the same.

Take a look at my album at~
http://home-and-garden.webshots.com/album/573614287PtzHVq
It should give you a good idea of what the growth rate on an Indian Giant ~ Sauromatum Venosum (AKA: Typhonium Guttatum / Arum Venosum) should be

Try a mix of Well Composted cow/horse manure, peat (or a high quality bulb or potting soil) mixed with sand, pumice & leaf litter / Organic mulch
Bone meal is also helpful

Also plant them in a pot that will give them plenty of room to grow
I've seen dime sized corms grow to 2 to 3in. round in a season & produce 8 to 10 new corms

They like warm with high humidity & are shade loving and like well drained soil that stays moist, but not to wet or soggy

Pretty much the same with A. Konjac

Hope this helps
E G G

http://community.webshots.com/user/EvilGardenGnome

I think you may be confused by the fact that everyone shows only their best tubers from their best growing season. I would say that anyone being truthful will say that some years they get huge growth and others not so much......it all depends on length of growing season for any given year, heat, humidity, etc. I've had many quadruple in size and other years they do not add any size......mine are not pampered babies in a GH......they have to deal with real conditions in zone 6.

If I were you I would leave them in the ground in zone 7....no need to dig them up.

Mine stay in FULL SUN here in zone 6.....no need for shade at all....all of my species are in full sun......they may grow a bit taller in shade, but so what.....they can capture more sun without burning in full sun. Am konjac can easily take full sun and so can Sauromatum venosum,.....the Indian Giant will only be about as large as the normal form in full sun, so if you want it big and tall put it in some shade, but otherwise don't sweat it.

Add a massive amount of fertilizer to try and get them big.....if they are in the ground add manure.....I add a couple of bags each year to the bed where I put them.....many stay in the ground forever and are fine.

Best of luck :o) Dan

Alright, thanks!

So now I have a follow-up question: When adding things like manure and other rotting organics, do I need to treat it?

Well, I buy mine at Home Depot or Lowes as a mix so it gets dumped out of the 40 pound bag and dug in to the soil that was there from last year......actually the place where I put mine for the summer is a huge dumping zone where pots get emptied every year so hard telling what all is in there now, but it is loose, drains well and they seem to like it....the Sauromatum are in our natural clay and could care less....they multiply every year and flower/fruit.....really, they can take a huge amount of abuse :o) Dan