Slack, in his two books, recommends an arrangement with a smaller clay
pot in a larger one so that water can be added to the space between
them to provide a controlled low level of moisture to the plant's
roots.
A short time after the seeds in the 10cm inch pot have germinated,
all but the one strongest plant are removed and discarded. Slack
believes that transplanting the seedlings, no matter how careful,
inhibits the growth of a full root system and the plants will die
within a year. He emphasizes that these plants do not tolerate root
disturbance.
The small pot is put in a larger 20cm one supported by a 2:2:1.5 peat,
potting soil, sand mixture so that the tops of the pots are more or
less even. The space between the pots is filled with long grain
sphagnum. The plant is then put in a very sunny place. When needed,
water is applied to the sphagnum only.
I live in a more arid climate (San Francisco bay area) and have not
found Drosophyllum to be as sensitive to root disturbance as Slack
describes. Once a raccoon ripped out one of my son's moderate size
plants, tossing it on the ground, completely exposing the roots. We
carefully put it back in its pot and replaced the medium (80:20
perlite and peat), where it lived nicely for another 2 or 3 years.
That experience gave me courage to carefully transplant seedlings
after I got my first seeds to germinate. Using a toothpick I very
carefully and patiently dig away the germination medium (50:50
perlite, vermiculite) to expose the root. Even when the initial
coiled leaves are only 3-4mm tall, the root is 2-3cm long.
I carefully put the seedlings in a mostly-mineral, very freely
draining soil mix. At first I used the perlite, peat mix. That mixture
works, but now I am experimenting with something more appealing to the
eye. Following Cheer's (Carnivorous Plants of the World) description
of its natural habitat, I have tried an 80:20 mix of 1/2 to 1cm
diameter silicate streambead gravel with shredded pine needles. That
has worked, I guess, but one of the plants I did this with is starting
to wane after about 3 years. Although it was very vigorous during
that span, I would like to have had it live longer.
One thing I am experimenting with now is the size of the pots. My son
noticed that the bigger pots seemed to have better plants, so we went
out and got two 30cm (12 inch) terra cotta pots! The idea behind this
is that the plant is adapted to living with small concentrations of
moisture by having a large volume root zone.
One of these pots we filled with 80:20 silicate streambed gravel + pine
needles. This plant died at the very end of our rainy season this
spring. The crown of the plant got too wet when it was warm (I grow
these outside).
The other pot was filled with 80-20 reddish mudstone gravel (1/4-1/2cm
diameter from a local roadcut) + shredded pine needles. The mudstone
seems to be porous (it crackles when water is poured on it), so it
should help buffer moisture levels better. Physically, I would expect
the mudstone gravel to act like crushed red brick chips of the same
size distribution. The plant in this mix is very vigorous and
1.5 years after germination it has 20cm long leaves.
The larger pots allow watering around the periphery so that the top of
the soil near the plant stays dry. The bottoms of my pots is not in
any sort of dish. They drain freely onto the ground.
So, go ahead and try your hand at growing this species. The main thing
to be mindful of is that it likes a soil with lots of air and not much
water. If the crown of the plant is wet when the temperature
approaches or exceeds 20C, it is very likely that it will die very
quickly from rot. Also, being a plant of arid regions, its very fine
roots can be sensitive to disturbance.
If the top of the medium is wet thoughout the day, then there is too
much water. On the other hand, if you aren't watering enough, the
plant will wilt, but if you water it before it completely dries out,
it will recover. I have had this happen several times and I haven't
noticed any short term ill effects.
When the plants are more than a year old, they should flower in the spring.
I let my plants selfpollinate. I am told that one gets fewer seeds this
way, but that they are larger. Since I get more seeds than I can handle, I
just leave the flowers alone.
Glenn Rankin
rankin@hpl.hp.com