Paul Temple (
Fri, 16 Dec 94 18:15:12 +0000

+---------------------------+ TM From: Paul Temple
| | | | | | | | Dept: Digital
| d | i | g | i | t | a | l | Func: Net Comms
| | | | | | | | DTN: 7781-1582
+---------------------------+ Easynet: fangio::temple_p

Not sure if this reply is wanted but I always feel an urge to comment
when Ping's are quoted as difficult to grow.

>It is not too easy to cultivate _P.vulgaris_ at home in a
>pot successfully (especially in winter; this is one of the reasons why I do
>cultivate it in vitro).
>Maybe Dr. Meyers-Rice could tell you more (Hi, Barry!), who has the alpine
>_P.leptoceras_ (which is impossible to grow for many European growers!) in
>Arizona (!!).

I used to find hardy Ping's impossible but then I discovered THE way.
P. vulgaris is incredibly temperamental in cultivation and it was this
plant that first showed me the way. I now grow all hardy Pings in a
clay pot and sink the pot into sand (in Alpine Plant circles, this is
called a plunge bench). I then keep the sand damp, NOT WET. I grow
the plants this way, outdoors, in full shade, covered by a clear
plastic lid (i.e. terrarium style) to maintain humidity and slow down
evaporation from the sand. Since doing this I have no losses,
including plants that I believe are P. vulgaris, P. macroceras, P.
grandiflora (in all its forms/subspecies), P longifolia (3 types)
P. valliosneriifolia and P. leptoceras. None of the above are
enthusiastic about standing water so the reputedly"normal" tray system
for watering CP's is not advised for hardy Pings.

The only hardy Ping I know of which does like standing water is P.
nevadensis which occurs wild in areas saturated with meltwater from
glaciers. I mimic this and they do fine, wet all the time they're
growing. I mimic using those camping ice blocks (the blue ones sealed
in plastic). I put one frozen pack into a bath of ordinary water,
every 12 hours. The P. nevadensis gows in soil, standing in rain
water, which in turn stands in the cold ordinary water which keeps it
all cool. I will be replacing this soon with a refridgerator, used to
pump cold rain water (stored inside the fridge) up to drop down by
gravity through the normal soil in which the plants grow. Kew gardens
go further than this. They bed the plant into soil which stands on a
freezing surface, to cause permafrost type conditions. All I can say
is that P. nevadensis doesn't grow in permafrost in the wild so it
comes as no surprise that Kew's P. nevadensis plants die!

All hardy Pings positively require a rest (when not grown in-vitro) in
which to go dormant. Without this they exhaust themselves and die. A
rest is initiated by decreasing day length in most cases, possibly
influenced by temperature drop. (In high altitude plants, e.g. P.
nevadensis, they must go dormant before snow arrives but while the
temperature is still high and day length long) so possibly dormancy is
triggered by time of year?). If you do not have naturally cold seasons
- and I mean reliably sub-zero cold, then you can mimic the
requirements by placing plants, still in their damp soil, into the
refridgerator. The cold sectiuon suffices for some reason. Freezing
is not necessary.

The best indicator of good conditions is that the plant lives. (Sorry,
I couldn't resist it!). The next best for hardy perennial Pings is a
measure of the number of gemmae produced. Poor conditions result in
low gemmae numbers and a poor strike rate for separated gemmae. Good
conditions result in more numerous gemmare which survive well when
sparated and repotted as described above for mature plants.

Hope this all helps someone.