DearAlison,
Itis my belief that even in the wild forest Alocasia often go throughperiods of boom and bust; with the plants reaching a peak of physicalperfection and the often soon afterwards ‘crashing’; thecycle in the wild seems to be ameliorated by the rejuvenation induced byregular leaf fall, but in pots there is a real danger that the pieces of the disarticulatedrhizome do not get the chance to rejuvenate before they run out of storedcarbohydrate, and then seem to lose the ability (will?) to re-grow.
Anotherfactor that is only now becoming clear is that Alocasia, and many other terrestrialaroids too, I suspect, have some mycrorrhizal association. I first began tosuspect this on finding super-vigorous specimens with infeasibly small rootsystems in the wild. Clearly the roots were too small to support the nutrientuptake that the plants needed, and yet the plants were thriving. The point wasreinforced by observations of litter-trapping Schismatoglottis, notably speciesin the S. barbata complex, where investigation of the leaf litterrevealed copious fungal hyphae and significant composting of the oldest leaf litter,with the plants rooting from the stem and through the leaf bases into thiscomposted material and the decomposing leaves above. From our experiments wehave observed a beneficial fungal population developing in the leaf litterwithin a couple of months, and a notable increase in plant vigour at this time.In fact, we no longer apply fertilizer to our plants (a considerable saving intime and money with ca 10,000 individual pots...) and this despite the factthat the nursery receives 5+ m of rain per anuum, and thus the flow-through ofnutrients from the pots must be considerable.
Onthe subject of watering, our plants get watered every day, either from ourvirtually daily torrential downpours, or, in ‘dry’ periods fromoverhead sprinklers. Even in dry periods humidity seldom drops below 70%. Thekey is well-drained media and making sure that the rhizome is not totallyburied. The crucial thing is that the leaf litter layer should not become dry(leaves crispy). The leaf litter (topmost leaves) remain damp and the leavesflexible.
Onenote, once you get the fungal hyphae community underway, the leaf litter willdecompose fairly quickly. We ‘top up’ the leaves regularly toensure that there are always fresh leaves on top of the decomposing andcomposted ones.
Verybest
Peter
From: aroid-l-bounces@gizmoworks.com[mailto:aroid-l-bounces@gizmoworks.com] On Behalf Of STARSELL@aol.com
Sent: 30 June 2009 05:43
To: aroid-l@gizmoworks.com
Subject: Re: [Aroid-l] Alocasias
Thank you much for posting this! I have two that I just
re-planted per your below Rx.
I knew they were alive but I had not seen much improvement
using the method I described, at least they were not continuing
I don't know what happened to them. All of my otherAlocasias
are thriving. One, a zebrina got knocked over and the stems
bent and would not straighten; the other a cuprea just randomly
began to droop until nothing was left but the tuber.
At least now I have some hope. The pots do look funnythough;
all that leaf litter. But now I have real hope.
One question - about watering this. Do you guess atit? Feel
the loam to see if it is damp? Go by the weight of the pot?
I wondered about leaving the loam only damp and moistening the
In a message dated 6/29/2009 9:38:06 A.M. Central Daylight Time, phymatarum@googlemail.comwrites:
Hi Tsuh Yang,
Many Alocasia literally 'climb' through layers of leaf litter, rooting as
they go, with the older parts of the elongated rhizome gradually senescing
and eventually dying. After much experimentation, and not a few deaths, we
have settled pots half full of a mineral soil (locally produce red topsoil
mixed with river sand in 1:1 mix), with the rhizome at most half buried, and
the remained of the pot filled with leaf litter. The root growth at the leaf
litter/mineral soil interface is extraordinarily vigorous and with the loose
leaves the problem of bacterial rot is resolved. I would suggest that you
try planting our dormant rhizomes in this manner and see what happens.
Peter
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