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Date: Fri, 02 May 1997 14:44:38 +0900
From: Greg Steenbeeke <gstee@dlwc.nsw.gov.au>
Subject: [14350] re [14300]: Pterostylis curta
Hi Roger and all other OLDers interested in terrestrials.
Ptst curta is probably one of the hardest Australian terrestrial orchids
to kill ! (;{) While it tends to be lacklustre against some of the other
native terrestrials it makes up for it's inadequacies in both the ease
with which it flowers and reproduces vegetatively.
A simple calendar would be:
Summer - Dormant - Time to repot into a good potting mix (don't use soil
Roger - soil kills plants in pots because it doesn't breathe). The mix I
use carries the Standards Australia mark (I don't know the equivalent for
OS users), and is about 1 part peat moss, 2 parts coarse sharp river sand
and one part fine pinebark (3-5 mm). Another mix is 2 parts peat, 2 parts
coarse sharp sand. Repot into a squat pot (eg 6" across x 4" high), with
the tubers about 2 - 3 cm below the top of the mix. Water well and leave
to drain. Water about every 7 to 14 days (depends on weather) until
growths appear.
The plants will break dormancy late in summer, and a small rosette of 2 to
6 leaves will form on the top of the mix. The leaves are spathulate
(spoon shaped) and have a short petiole (stalk). Each can get to 5 x 2
cm. Water well, but don't keep it too wet. A drier-side-of-damp condition
is just right.
Many Australian terrestrial species are winter-growers, as that is the
wet season for the southern half of the continent where these plants
abound. We don't have to worry too much about cold, but bushfires
would claim any summer-growing plants.
A single flower stem to 30 cm arises from the centre of the rosette, and
will carry a solitary flower to 5 cm tall. The flowers are green and brown
with some white. The lip is brown, and usually protrudes from between
the fused sepals. It is twisted around slightly (about 90 degrees) so the
"top" points to one side. This is one of the characters of the species -
it's not a sign of poor culture!
I believe there is a pic of Ptst curta (or another Ptst sp) at my friend's
website :
http://metz.une.edu.au/~mgray2/
Flowering usually occurs late winter to spring.
After the flower dies off, let the plant dry out. This is important,
as rot will claim the tubers if you don't let them rest. Repotting
only needs to be done about once every 2 -3 years, although more
frequent repotting can be done. The plants may reproduce at the rate
of 4x to 6x per year! one of the best displays of the species I have
seen was in a foam "fruit box", with maybe 300 flowering plants. It
had started from 10 plants only 4 years earlier!
One other thing - and a source of great amusement - is to lightly touch
the tip of the labellum when it is in the "set" position (ie - pointing
forwards). It will spring back to the back of the flower, about as quick
as a Venus' Flytrap. This is the pollination mechanism. An insect lands on
the labellum, and is thrown into the base of the flower. It must then
climb up the tube formed between the column and lip, past the stigma then
the anther, effecting pollination on it's way. It's a great way to amuse
young kids (if you have enough flowering!)
Good luck with them - they are very rewarding and quite forgiving!
Greg Steenbeeke
Date: Mon, 05 May 1997 17:12 -0400 (EDT)
From: Orchidees <orchidees@dunord.com>
Subject: [14496] pterostylis curta
Hello Roger,
Pterostylis orchids are indeed Australian terrestrial orchids. They have
true subterrean bulbs (not pseudobulbs) that remain the only living part
of the plant during their rest period.
One important part of their life cycle is that they go dormant during
hot weather instead of cold weather (like most other bulb plants that I
know, including orchids). This is an adaptation to a very hot an dry
summer in Australia. The plants lose their leafs at the beginning of
summer and come alive when temperature goes down again and rain starts
falling. They must also be protected from frost since their adaptation
is to hot weather, not cold.
I recently purchased several terrestrial orchids from Nesbitt Orchids in
Australia, including Pterostylis concinna that seems close to flowering
(along with some caladenia and thelemytra). His growing recommendations
were as follows.
Soil mix 45% loam
50% sand
5% organic matter
a little bloud & bone fertiliser
cover the soil surface with a mulch of pine or sheok
needles
replant each year at the end of the dormant period.
Use a 4" (10cm) pot or larger if you have more than one
bulb.
Pterostylis like approximately 50% shade. I am growing mine under
Phalaenopsis light.
During active growth (6 to 8 months / 5-20C max, 0-14C min) keep the
soil humid. During dormant period (4 to 6 months / 18-40C max 12-30C min),
protect plant from water. It is also a good time to examine the tubers.
Be very carefull with fertilizers because some terrestrials can be
burned or killed by overuse. Pterostylis however will benefit from weak
applications of folia fertilizer in early growth.
These are Mr. Nesbitt recommendations which, of course, needed some
adaptation to our Canadian growing conditions. I used sieved perlite
instead of sand, chopped oak leaves for organic matter, and cut tree
fern since I could not find pine needles under a meter of snow and had
not the slightest idea what a sheok could be.
Since bulbs were actually coming out of Australian summer, Mr. Nesbitt
recommended that we should give them a short growing season. I am thus
planning to keep the plants inside the house this summer in a cool place
and keep them warm and dry starting at the end of September. By next
summer, they should be in sink with our Norther Hemisphere growing
season.
Pterostylis are reputedly easy to grow and many grow in colony, a mother
plant producing more than one tuber for the next growing season (
although I do not know if this is the case for P. curta). I think the
most important factor for success is understanding their hot/cool
growing cycle.
Hubert Ricard
An orchid a day
Keeps the doctor away
If you don't use too much pesticides
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