being said, there is no one "correct" way of providing your plants
with a dormant period, and your mileage may vary. This article
presents 2 methods that I have found to be successful - the classical
cold dormancy, and a dry dormancy (not to be confused with the
hot dormancy seen in some winter-growing CPs, such as tuberous,
pygmy and petiolaris-complex of Drosera).
PLANTS NEED DORMANCY?
the commonly-grown CPs amongst hobbyists here, this is just a
short list that is nowhere near comprehensive:
muscipula (Venus fly trap)
- cold-temperate species and forms
- cold-temperate species
species and hybrids
- usually the very few that produce tubers or turions in winter
DORMANCY, PREPARATION & PRECAUTIONS
of the fundamental rules is: do not force dormancy on your plants
- if they are ready, they will start entering dormancy on their
own. Therefore, our role is to recognize when they need a rest,
and to provide conditions required for this rest.
this is usually the trickiest part. The recognition of dormancy
especially in the tropics is rather an art more than exact science,
and cruelly tests your observational skills. Different genera,
species, and even plants of the same clone can present differently
when they need a rest, but these are some clues for recognizing
Dionaea muscipula "Shark's Teeth" - summer growth form.
The exact same plant shown above, postively screaming for
dormancy. Notice the ground-hugging growth form, widened petioles
and smaller traps.
Healthy, trap-forming growing tips of a Sarracenia
plant, fresh out of a dry dormancy and with a flower bud
New leaves of a Sarracenia just going into dormancy.
Note the weakly-formed leaves devoid of the normal trap shape.
As these grow out, they form phyllodia instead - leafy structures
that do not function well as traps.
you are fairly sure that your CP is going into dormancy, doing
a few things in advance will help greatly. First, gradually -
GRADUALLY, not parch them! - reduce the amount of water they are
receiving. I usually take them off the tray watering method and
start watering them as per normal houseplants, allowing the peat
to become just barely moist before watering again. Second, gradually
decrease the photoperiod. This is exceedingly-difficult to achieve
in Singapore, but an acceptable way is to place them at a east-facing
location where they receive only direct morning sun. If not, simply
placing them in a shady position would also suffice.
again, no strict rules on this - but I usually prepare this pre-dormancy
treatment for at least 2 weeks before starting on the real thing.
dormancy eventually involves putting your plants to rest in a
cold, slightly-moist environment, usually the crisper (vegetable)
compartment of a regular fridge.
remove the plant carefully from its pot. Remove as much old peat
from the roots as possible, and inspect the plant and rhizome
for any old, dead and dying leaves. These should be snipped off
to prevent the growth of any fungus.
Dionaea freshly-removed from their pots.
and washed - for Dionaea, I remove the older roots
Likewise for Sarracenia, old leaves are trimmed down.
that cold + dark and damp + dormant plant = fungus galore! As
a further precaution, lightly mist the entire plant with a mild
fungicide. I've been using a simple one, Captan, for many years
with good success.
some dried, long-fibre sphagnum and squeeze most of the water
out so that the sphagnum is just damp. You can spray this sphagnum
again with fungicide if you wish.
a suitable plastic bag. I like to use those with holes already
punched into them, to encourage some air circulation. However,
this also means that the sphagnum will dry out much faster than
if you used a sealed bag. Layer the bottom of this bag with some
of the sphagnum, place your CP on top of the sphagnum, and finally
cover the plant up with more sphagnum.
Bottom layer of damp sphagnum, in a bag with holes.
Next layer - the Dionaea themselves.
Finally, covered with a top dressing of sphagnum.
to label the bags! Use a marker pen to indicate the plant's identity
and especially the date of dormancy. Seal the bag up, and place
it into the crisper compartment of your fridge. The bags should
be checked about once a week for any signs of fungus, and also
make sure that the sphagnum remains damp.
Whole fridge filled with dormant plants!
Sarracenia lost to dehydration and fungus while I was
away on holiday.
of using a fridge, I find that dormancy can also be achieved outdoors.
I favour this method for its simplicity, and the plants still
seem to do just as well as those with a cold dormancy. For a dry
dormancy, the pre-dormancy treatment becomes of utmost importance,
and can stretch for as long as 4 weeks. At the end of this period,
place the plants - pot and all - in a shady area which does not
receive any rain.
must be strictly controlled such that the peat remains just very,
very, very barely damp all the time. Never overwater, and never
let the peat go bone-dry either! This is especially useful for
the less fussy, such as Dionaea, Drosera and most
Pots of Sarracenia taken off the trays and put
aside for pre-dormancy treatment before a dry dormancy.
period of actual dormancy varies, so your best bet would be to
observe the plants for any signs of vigorous, new growth. This
typically takes about 2 months for most plants, and 3 months or
more for plants with naturally-extreme localities such as Sarracenia
purpurea ssp. purpurea. Once new growth starts, pot
the plants back up and commence watering slowly, and they can
eventually be returned to the tray system once growth has become
steady and vigorous.
Signs of new growth on a Dionaea, after 2 months in
the fridge. Note the now-upright new leaves, in contrast with
the old winter leaves with large petioles.
THE AUTHOR & ACKNOWLEDGEMENTS
Culture Singapore (GCS) would like to thank Hong Yee for sharing
this informative article with our members and now, with CPers
on the World Wide Web!
Yee is currently a moderator for the Carnivorous Plants Section
of the GCS forum. He has been keeping these CPs since 1994, experimenting
with varying outcomes on growing carnivorous plants in Singapore.
his personal website, named "Little Garden of Horrors"
after the famous 1982 broadway hit "Little Shop of Horrors". There
is an introduction to CPs in general, as well as tips on growing
them successfully, especially in hot, lowland climates like Singapore.