Hello all,

I have grown a Cypripedium formosanum for 4 years now and it has always grown well (see here (http://www.slipperorchidforum.com/forum/showthread.php?t=12585) its flowers and history last season).

I grow it in a large pot outside all year long. However, this winter was more cold than the ones we had those last years (about -8°C this year). This Cyp. is now sprouting but it has only 2 growths this year (4 last year) and I have seen rotted buds in the soil.

So, my guess is that it did not like the cold temperatures at all, event if it is said frost resistant. What do you think about this? Thnank you in advance for your help.

Best regards,

Mafate.

I don't know anything about cyps but I'm sorry to hear that. Maybe the two sprouts will grow and bloom.

I hope the two remaining growths grow to maturity and bloom! Did you place the pot buried underground to avoid freeze if you had left it outside?

hey, this is a pic from my C. formosanum from yesterday.

http://img142.imageshack.us/img142/8743/1formosanum09.jpg

the plant is growing in a large 35 cm pot,
plunged in the soil.
we had minus 16 Celsius this winter,
but also lower temps in last years,
and I never had any damage to the plant.

the plant is now about 20 years old,
but divided several times,
(to give away divisions)
it grows in pure fine sand,
covered with about 2 cm partly composted fir bark.
fertilized regularly.........

cheers
dieter

Hope it lives and blooms!!!

Nice plant Dieter. Do you take the pot out of the ground each summer?

Cyps in general, with no exceptions that I can think of, are subject to problems regardless of how long you've grown them. Plants that are relatively new (say, less than 5 years in cultivation) should not be considered established plants yet and are even more vulnerable. It is hard to know what your plant's problem is without inspecting the roots. Rotting of buds usually is a pathogen problem, although mechanical damage could lead to rot as well. Probably a good idea to lift the plant now before it grows more to see what's up.

I wouldn't leave pots exposed outside in the winter, though some folks do. Potted plants should be put on the ground at least and covered with a thick mulch layer (about 30 cm). I know a grower who lost a C. reginae this winter because it was in an exposed pot. It is likely that freezing and thawing cycles caused its death.

That plant is looking nice!
I hope your plant does well this year despite the cold, Mafate.

Deiter,
That formosanum looks fantastic! Makes me want to try it...although, I know they tend to green up at the earliest sign of warm weather and often get frosted.

Mark

......... Do you take the pot out of the ground each summer?

the pot is only, that the plant will not "escape".
it is like shown in the pic all year long.
I only lifted the pot for dividing,

but in winter I cover with a poly and some additional mulch,
but this year we had a "lot of snow".
a lot means in Berlin 30 cm :-)

Maybe too wet from excess of snow melt and freezing again in winter? The surrounding soil would need to be very free draining as well as the mix the cyp is in, I can only think it was too wet over winter when this one would like to just stay moist. -8c is not a problem.

or too many orgainics in the potting mix and over time losses its poreosity. Whats your potting mix and whats is the surrounding soil like?

Hello all,

thank you for your answers. I think that you are right: my mistake was to keep the plant potted but the pot outside the soil. All the growths of my plant were just next to the wall of the pot, and therefore very exposed to low temperatures. I will be very careful next winter.

Thank you again and best regards.