Rheum nobile/alexandrae

[Bjarne]

Rheum alexandrae grows without any problem by me, even in purest peat and without any care, but anyway it might be of easier culture then.
But would the superficial likeness be a little clue to any growth/climate requirements similarities with nobile, or not at all?

Rheum alexandrae from Tianchi lake 3850m, Zhongdian, Yunnan. It grows in quite damp in peat soil

[ArnoldT]

OK, what's the flower in the background.

[Bjarne]

If you mean the image with R. alexandrae it is Primula secundiflora (and Rhododendron rupicola).

[ArnoldT]

Yep, that's it.

I see I can buy it right nearby in Maine.

[arilnut]

Arnold, where!!?

John B

Yep, that's it.

I see I can buy it right nearby in Maine.

[johnw]

If you mean the image with R. alexandrae it is Primula secundiflora (and Rhododendron rupicola).

Funny Bjarne, before I read your rupicola I was thinking chryseum. Half right. growing near the lake says something about their dislike of drought eh?

johnw

[Lesley Cox]

Two more seedlings up this morning. I should have counted the seeds. I usually do if there are 10 or fewer, so maybe 12-15.

Bjarne, please explain more, your system for R. nobile. I take it the plastic containers are to be reservoir rather than planting container? Is that right? I can't see where the containers have been stowed, in the second picture, trying to match the rocks in the two. Where is the tap and where exectly is the plant?

[ArnoldT]

John:

http://www.evermaynursery.com/store/index2.asp?ID=84

Old Town Maine.

[Lesley Cox]

There don't seem to be any Rheums listed in their current catalogue.

[ArnoldT]

Lesley:

it was the Primula I was referring to.

[Lesley Cox]

Oh, sorry, that would explain why I couldn't see rheums.

[Bjarne]

Bjarne, please explain more, your system for R. nobile. I take it the plastic containers are to be reservoir rather than planting container? Is that right? I can't see where the containers have been stowed, in the second picture, trying to match the rocks in the two. Where is the tap and where exectly is the plant?

Hi Lesley
I'm not so good to explain in English so I have tried to make a sketch. Hope you can see from the sketch how it is done :-)

The photos do not show Rheum since it is only a small seedling and the tap does not show either, since it is hidden behind one of the lower stones.

[Lesley Cox]

Thanks Bjarne, yes, that helps a lot. I see what you mean now.

[Philippe]

Well it's a while since we posted here but I have good news this morning (Mar 11th) in that I have 7 seeds germinated overnight, of Rheum nobile from Holubec seed. The seed was sown on February 22nd. There are several other little bumps in the grit which I expect to be seeds up within a day or so and I'll take a picture when it stops raining. That may have helped; we have had rain almost every day/and or night for about 3 weeks and the seed pots are quite wet. I guess germinating is the easy part and now I'll have to work out what to do with them as they grow a little. It may be that they should be separated and potted individually while still very small rather than disturb the roots too much. I'm tempted to try some in long tom pots with a very high proportion of gravel and grit, with a little humus. Any suggestions or advice will be gratefully received. As for flowering them, that's a long way off yet, if it ever happens.

Hi Lesley

Great that your rheum nobile seeds have done so well! I had found too that germination was generous.
Last year, I have lost 3 seedlings in the few weeks following repoting. Aside from the possible repoting stress ( but in my opinion not that great in comparaison with other more delicate generas), I guess the weather was simply too wet last summer, and my poting mix was probably not free draining enough.
I even wonder if, for me, it isn't more complicate to try to grow them for too long in pot during their younger lifes, or I have to find really the perfect adequation between faultless drainage and sufficient watering, according to the plant growth and strength. And there seems to be not the littlest place for any mistake in this combination. I can't keep an eye on the seedlings during winter, they have to live alone for 6 months between november and april, with or without snow cover, with or without rain, with or without damaging frosts. So, in my case, I think they can possibly get through this crucial period better if directly planted in the bed.
For the next time to come I will try to sow 2 or 3 seeds in each sowing-pot, wait the summer months to let the seedlings get a bit stronger, and then repot the whole seedling-pot directly in open ( well prepared) ground in autumn, without any root disturbance. For such big adult plants, I have long found that many 1/2 years seedlings of different genera/family generally do better when quickly put in the ground ( preferably in a dedicated multiplication bed, where they can still be watched closely).
I'll tell in a few weeks what will be the result of my last-year nobile-seedlings. Hope there will be something to tell!

[Lesley Cox]

I think all mine must have germinated by now. There are 12 seedlings, none as yet with second, true leaves. I'm thinking it may be a good idea to pot each one separately now, before the roots become too long. I have no garden place suitable to plant them out so will have to keep them potted for at least a year. I'm thinking of a mixture of humus, gravel and grit as a possibly suitable mixture.