[pbs] Alocasia and Colocasia
Aqua Flora
aquaflorasa at telkomsa.net
Wed Feb 25 16:03:07 EST 2009
Dear Bob,
In addition to what has already been said, I'd like to add that Colocasia
are hungry and thirsty plants! I grow about 17 different varieties of
Colocasia all of them standing in water. Colocasia do not need to stand in
water, and will grow happily under normal moist garden conditions, but will
grow much bigger, better and faster if given lots of water.
Secondly, Colocasia prefer to grow in the full sun, most will also do well
in partial shade, but many of the dark leaved varieties such as C. esculenta
'Black Magic' and C. esculenta 'Midnight' tend to have a washed out colour
when shade grown. Others like the dwarf C. fallax are much more shade
tolerant.
Apropos Byron's comments on growth medium, Colocasia will grow very well in
a rich compost-based medium, but as he rightly notes it will float out of
the pot once submerged in a pond. The solution is to use a heavy clay-like
loam / top soil / dirt / whatever you want to call it! You can use the same
soil that is recommended for waterlilies and most other marginal aquatic
plants. Personally I like to use equal parts heavy loam and composted bark
together with a generous portion of bone meal and bounceback, this ensures a
rich heavy medium that will not float out of the pot!
Lastly, the question of dormancy comes to mind. As most (if not all)
Colocasia species originate from SE Asia, I think it is safe to assume that
they do not require dormancy and will happily grow year round if you can
provide adequate heat and light. But they will go dormant in temperate
climates. Depending on how cold it gets they may be left outdoors where
their leaves will die back, but the underground tubers will remain unharmed.
Most of the commercially available varieties are reportedly hardy to Zone 7b
(-12.3 to -17.7 C). From what I've read hardiness increases if plants are
kept on the dry side during winter. In colder zones it is recommended that
tubers be dug up in fall and stored in moist peat or similar medium in the
basement. Fortunately I have a relatively mild climate and can leave my
Colocasia in the pond year round where they do not go dormant but do look
rather "ratty" during winter.
I might just as well add that there are approximately 8 species of Colocasia
and many more cultivars. The ornamental varieties have become very popular
of late, and as Byron noted Plant Delights Nursery does have a mouth
watering selection of new cultivars from Hawaii. There is also a large group
of culinary Colocasia (perhaps even more varieties than of the ornamental
types). These have been cultivated in Tropical Asia since 5000 BC (some
sources say 8000 BC), and is the oldest cultivated crop in the world! The
starchy tubers can be boiled or the leaves can be cooked as a green
vegetable. As all parts of Colocasia contain calcium oxide crystals, it has
to be boiled for several minutes to render them safe to consume. Reputedly
some varieties have better flavour and texture than others, but I must admit
that I have never tried them ;-)
If anyone is interested in trading I have offsets of most varieties
available.
Bob, I hope this answers your questions!
Kindest regards,
Pieter van der Walt
(South Africa)
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