DearJohn,
Apologiesfor the slow reply; have just been attending the Nancy aroid conference, thento Munich to Josef’s collection, and then to Firenze to work in theBeccari Herbarium; just back today.
Alocasiarobustais not easy and invariably reacts very badly to transplanting. We havefound the only way to grow successfully it is to plant ex vitro into thefinal size pot (looks ludicrous for a long but works) or to sown seeds (3 -4)into the final size pot or final growing place.
Inthe wild it is a gap-phase plant, and in cultivation needs nearly full sun orvery light shade. It is also definitely a plant for a mineral soil; in habitatthe largest plants are always in the local terat series red soils with lightleaf litter cover.
Verybest
Peter
From: aroid-l-bounces@gizmoworks.com[mailto:aroid-l-bounces@gizmoworks.com] On Behalf Of John Criswick
Sent: 04 July 2009 02:19
To: 'Discussion of aroids'
Subject: Re: [Aroid-l] Alocasias
DearPeter,
Do you have any thoughts about the difficulty of cultivating A. robusta? I got one growing nicely in a 10” pot, but on planting it in nice,leafmouldy, well drained soil, it went into reverse and disappeared. Of courseI couldn’t grow it to maximum size in a container.
John.
From: aroid-l-bounces@gizmoworks.com[mailto:aroid-l-bounces@gizmoworks.com] On Behalf Of Peter Boyce
Sent: Wednesday, July 01, 2009 6:56 PM
To: 'Discussion of aroids'
Subject: Re: [Aroid-l] Alocasias
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 thedisarticulated rhizome do not get the chance to rejuvenate before they run outof stored carbohydrate, and then seem to lose the ability (will?) to re-grow.
Anotherfactor that is only now becoming clear is that Alocasia, and many otherterrestrial aroids too, I suspect, have some mycrorrhizal association. I firstbegan to suspect this on finding super-vigorous specimens with infeasibly smallroot systems in the wild. Clearly the roots were too small to support thenutrient uptake that the plants needed, and yet the plants were thriving. Thepoint was reinforced by observations of litter-trapping Schismatoglottis,notably species in the S. barbata complex, where investigation of theleaf litter revealed copious fungal hyphae and significant composting of theoldest leaf litter, with the plants rooting from the stem and through the leafbases into this composted material and the decomposing leaves above. >From ourexperiments we have observed a beneficial fungal population developing in theleaf litter within a couple of months, and a notable increase in plant vigourat this time. In fact, we no longer apply fertilizer to our plants (aconsiderable saving in time and money with ca 10,000 individual pots...) andthis despite the fact that the nursery receives 5+ m of rain per anuum, andthus the flow-through of nutrients 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.com writes:
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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