TOW Roscoea

TOW Roscoea
Robert Hamilton (Mon, 10 Feb 2003 02:59:57 PST)

Hi all,

Roscoea is a small genus of late spring / summer growing plants
of the ginger family , Zingiberacea. They have a growing point
from which a cluster of thickened roots decend , somewhat like a
Dahlia but in minature form. The leaves are reminiscent of a
minature sweet corn, with flower at the apex , which to my eye

is somewhat orchid like (thinking Masdevallia) with one large
decending petal and several smaller petals above and beside the

main petal. They originate mainly from India, Nepal and China.

In Tasmania they need partial to full shade and additional
summer watering to grow well. They tolerate moisture when
dormant and do equally well in the ground or pots. For those in

cooler climates they are said to be outdoors hardy in Britian.
They germinate easily from seed . When sown in late summer
germination usually occurs in autumn, while seed sown in early
spring emerges with the timing of mature plants. Some species tend

to seed around a bit including into adjacent pots. Mature plants

can be divided in winter.

The biggest problem with Roscoea is identification of the species.
Several species have been perpetually misnamed . The best treatment

I have read of the genus is by Richard Wilford from RBG Kew in
the March 1999 quarterly bulletin of the Alpine Garden Society.

I grow the following but cannot absolutely guarantee the identity

of my species.They range from 5cm (2 inches ) to 30cm (12 inches)

tall.

Roscoea alpina - a small species with mauve to purple flowers
which is easily grown and seeds freely.

Roscoea australis - small purple / mauve flowers similar to
alpina but has broader and shorter leaves.

Roscoea auriculata - this plant has been distributed in Australia as

Roscoea purpurea or purpurea procera. It grows well but does not
tolerate too much sun - I often find it wilting after a warm day,

but it recovers with a good water in the evening. Flowers are a

deep violet-purple. The auriculata refers to the ear shaped first
leaf on the pseudostem.

Roscoea cautleoides - in its yellow form it is easily recognised

but purple and white forms are becoming available with the
explosion of new plant material from China. I find it needs help

to set seed and the seeds are difficult to recover from amongst
the bracts.

Roscoea humeana - this has a large hooded dorsal petal , larger
than the labellum giving it a distinct appearance. It is commonly

purple , but yellow , cream and white forms do occur. My
seedlings are reasonably new but it seems to be a vigorous =
grower.

Roscoea purpurea - this is the type species which was described

in 1806. Flowers are pale purple or mauve. It is said to be
the most vigorous species growing up to 50cm ( 20 inches ) tall.

I have kept my original plant in a pot and have not found it

to be this vigorous, but it has quite broad and heavy leaves. I

intend to plant in the garden next spring as I now have my
own seedlings . To illustrate the difficulties with identification I

have now almost convinced myself that my plant is R capitata - my

plant has flowers of rich deep purple on a long peduncle- seen the

image.
A red form of R purpurea was discovered in 1994 a unique colour in

the genus.

Roscoea scillifolia- this is the smallest of the genus growing
little more than a few cm tall. The flowers can be pink , purple

or white. I have a pink form whose flowers are fairly fleeting.
It seeds around quite freely and appears last of the species I

grow - in flower at present in early February.

Roscoea tibetica - my plants are still unflowered seedlings. It is

another small species with typically dark purple flowers , which

can also range from violet to mauve , rose or white. The
photograph in the AGS article shows horizontal lateral petals
making it look more like a typical orchid flower.

The following list of species I have not grown is taken from
the AGS article.

Roscoea Beesiana - a vigorous hybrid between auriculata and
cautleoides with variable amounts of violet striping.

Roscoea capitata -rich deep purple

Roscoea forrestii- small , yellow or purple flowers.

Roscoea ganeshensis - a recently discovered species from Nepal.
Pale purple flowers , with narrow dorsal petal is a paler colour

than the rest of the flower.

Roscoea praecox - a new species collected on the Alpine Garden
Society China Expedition. Purple with up to six white lines on the

base of the labellum.

Roscoea schneideriana - dorsal is pale pinkish -purple with rest of
the flower a darker violet-purple.

Roscoea tumjensis - dark purple similar to humeana with labellum
larger than the dorsal petal.

Roscoea wardii - purple flowers.

I have posted some Roscoea to the wiki which I have dragged out of

my archives - none are photographic masterpieces but give some
idea of the species available.

http://pacificbulbsociety.org/pbswiki/index.php/…

Roscoea alpina - sorry I didnt remove the dead flower.

Roscoea auriculata makes an attractive small clump.

Roscoea capitata - obtained as seed as R purpurea but my =93homework=94=

makes me think this is the correct name - in reality it is a rich

deep purple.

Roscoea cautleoides- the colour is a little washed out on this image

Roscoea humeana -the split dorsal petal is not a normal feature but

the image illustrates its =93fuller =93 flower.

Roscoea ?Beesiana- this is Lyn=92s image of a plant she obtained as =

R cautleoides which we think may be the hybrid R Beesiana, said to

have variable violet striping.

Rob in Tasmania

Temperate Marine Climate -equivalent USDA 8-9
Very occasional extremes -2 C ( 29 F) to 39 C (101 F).
Average rainfall 27.7 inches - fairly evenly spread.

I have nothing important to add to Rob's introduction regarding culture

and
species, I don't grow quite as many types in my garden. Different little
plants that flower in the heat of summer in the shade are most
welcome,and
the flowers are delicate little beauties. I have found they do better in
pots for me than in the ground but that is probably because of
competition
from trees and shrubs for water during hot spells.They certainly are not
difficult to grow as long as they have enough water and protection from

the
sun.
The conditions here in Canberra are probably harsher than in =
Rob's
Tasmanian garden, this is a long way north on the mainland and inland as
well ,where we have long hot dry summers with temperatures up in the =
high
30's C (90=92s F) and winters with many night time frosts down to -9 C =
(16
F) at times and Roscoeas handle this without problems with little
protection. I wish they
grew as lushly here as they do in the U.K.,I remember particularly how
beautiful they were growing in the Lakes District Horticultural Society
garden at Holehird.

Lyn in Canberra

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charset=WINDOWS-1252

Hi all,

<underline><fontfamily><param>Doctor</param>

</fontfamily></underline><fontfamily><param>Doctor</param>Roscoea is
a small genus of late spring / summer growing plants of the
ginger family , Zingiberacea. They have a growing point from
which a cluster of thickened roots decend , somewhat like a
Dahlia but in minature form. The leaves are reminiscent of a
minature sweet corn, with flower at the apex , which to my eye
is somewhat orchid like (thinking Masdevallia) with one large
decending petal and several smaller petals above and beside the
main petal. They originate mainly from India, Nepal and China.

In Tasmania they need partial to full shade and additional
summer watering to grow well. They tolerate moisture when
dormant and do equally well in the ground or pots. For those in

to seed around a bit including into adjacent pots. Mature
plants can be divided in winter.

The biggest problem with Roscoea is identification of the species.
Several species have been perpetually misnamed . The best
treatment I have read of the genus is by Richard Wilford from
RBG Kew in the March 1999 quarterly bulletin of the Alpine Garden
Society.

I grow the following but cannot absolutely guarantee the
identity of my species.They range from 5cm (2 inches ) to 30cm
(12 inches) tall.

Roscoea alpina - a small species with mauve to purple flowers
which is easily grown and seeds freely.

Roscoea australis - small purple / mauve flowers similar to
alpina but has broader and shorter leaves.

Roscoea auriculata - this plant has been distributed in Australia as

Roscoea purpurea or purpurea procera. It grows well but does not
tolerate too much sun - I often find it wilting after a warm
day, but it recovers with a good water in the evening. Flowers
are a deep violet-purple. The auriculata refers to the ear shaped
first leaf on the pseudostem.

Roscoea cautleoides - in its yellow form it is easily recognised
but purple and white forms are becoming available with the
explosion of new plant material from China. I find it needs
help to set seed and the seeds are difficult to recover from
amongst the bracts.

Roscoea humeana - this has a large hooded dorsal petal , larger
than the labellum giving it a distinct appearance. It is commonly
purple , but yellow , cream and white forms do occur. My
seedlings are reasonably new but it seems to be a vigorous
grower.

Roscoea purpurea - this is the type species which was
described in 1806. Flowers are pale purple or mauve. It is
said to be the most vigorous species growing up to 50cm ( 20
inches ) tall. I have kept my original plant in a pot and
have not found it to be this vigorous, but it has quite broad
and heavy leaves. I intend to plant in the garden next spring
as I now have my own seedlings . To illustrate the difficulties
with identification I have now almost convinced myself that my
plant is R capitata - my plant has flowers of rich deep purple
on a long peduncle- seen the image.

A red form of R purpurea was discovered in 1994 a unique colour in
the genus.

Roscoea scillifolia- this is the smallest of the genus growing
little more than a few cm tall. The flowers can be pink ,
purple or white. I have a pink form whose flowers are fairly
fleeting. It seeds around quite freely and appears last of the
species I grow - in flower at present in early February.

Roscoea tibetica - my plants are still unflowered seedlings. It is
another small species with typically dark purple flowers , which
can also range from violet to mauve , rose or white. The
photograph in the AGS article shows horizontal lateral petals
making it look more like a typical orchid flower.

The following list of species I have not grown is taken from
the AGS article.

Roscoea Beesiana - a vigorous hybrid between auriculata and
cautleoides with variable amounts of violet striping.

Roscoea capitata -rich deep purple

Roscoea forrestii- small , yellow or purple flowers.

Roscoea ganeshensis - a recently discovered species from Nepal.
Pale purple flowers , with narrow dorsal petal is a paler
colour than the rest of the flower.

Roscoea praecox - a new species collected on the Alpine Garden
Society China Expedition. Purple with up to six white lines on
the base of the labellum.

Roscoea schneideriana - dorsal is pale pinkish -purple with rest of
the flower a darker violet-purple.

Roscoea tumjensis - dark purple similar to humeana with labellum
larger than the dorsal petal.

Roscoea wardii - purple flowers.

I have posted some Roscoea to the wiki which I have dragged out
of my archives - none are photographic masterpieces but give
some idea of the species available.

http://pacificbulbsociety.org/pbswiki/index.php/…

Roscoea alpina - sorry I didnt remove the dead flower.

Roscoea auriculata makes an attractive small clump.

Roscoea capitata - obtained as seed as R purpurea but my
=93homework=94 makes me think this is the correct name - in reality =
it
is a rich deep purple.

Roscoea cautleoides- the colour is a little washed out on this
image

Roscoea humeana -the split dorsal petal is not a normal feature
but the image illustrates its =93fuller =93 flower.

Roscoea ?Beesiana- this is Lyn=92s image of a plant she obtained as

R cautleoides which we think may be the hybrid R Beesiana, said
to have variable violet striping.

Rob in Tasmania

Temperate Marine Climate -equivalent USDA 8-9

Very occasional extremes -2 C ( 29 F) to 39 C (101 F).

Average rainfall 27.7 inches - fairly evenly spread.

I have nothing important to add to Rob's introduction regarding
culture and

species, I don't grow quite as many types in my garden. Different
little

plants that flower in the heat of summer in the shade are most
welcome,and

the flowers are delicate little beauties. I have found they do better
in

pots for me than in the ground but that is probably because of
competition

from trees and shrubs for water during hot spells.They certainly are
not

difficult to grow as long as they have enough water and protection
from the

sun.

The conditions here in Canberra are probably harsher than in =
Rob's

Tasmanian garden, this is a long way north on the mainland and inland
as

well ,where we have long hot dry summers with temperatures up in the
high

30's C (90=92s F) and winters with many night time frosts down to -9 C
(16 F) at times and Roscoeas handle this without problems with little
protection. I wish they

grew as lushly here as they do in the U.K.,I remember particularly how

beautiful they were growing in the Lakes District Horticultural Society

garden at Holehird.

Lyn in Canberra

</fontfamily>=

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