Rheum nobile/alexandrae

[Philippe]

A last look at Rheum nobile for this season 2014.

Recently I had to plant out the weakest of the 3. It just didn't progress this year, and I wanted to understand what was wrong before risking losing it. May it be the soil mix or whatever, but the main taproot was broken or rotten a few centimeters under the collar, so that the plant only survived with some lateral secundary roots born above. It was planted in another place meanwhile, with new soil, to see if it can get a new chance.

The other 2 begin to get impressive plants. Partly because they are Rheum nobile I guess, because every other more common rhubarb species would still be called smallish at that stage...





The very wet and fresh weather we had nearly during the whole 2 months July and August with many days in fog really pleased them.
Let's hope they now get a good winter.

[Lesley Cox]

Well done Philippe. VERY well done. They certainly ARE impressive. I wish you whatever kind of autumn/winter will suit them best, and look forward to hearing good news in the spring.

[Philippe]

Update 2015.

First of all, one pic.



I really don't know what to think of it...I know garden and plants always look awful at the very beginning of the new seasons, but I really have doubts this year about Rheum nobile...Both plants look similar for the moment, and the third one, the weakest one I wanted to save last year, seems to have disappear meanwhile.
Rhubarbs in general here are often notorious for showing almost immediately the new red shoots pointing as soon as the snow has melted. So did untill now Rheum nobile too.
At that place where the nobile are planted, the snow is away since 2 or 3 weeks at least, and there have been some really mild days meanwhile. So still no new shoots?  I fear the worst... I guess I'll be sure if there's no change in 2 weeks!

[Philippe]

Here they are again, both Rheum nobile!
Actually, the emerging new red leave just appeared on both plants only 3/4 days after I took the first picture.
I gave for the first time a slight hint of fertilizer, in form of roasted horn powder.
I got some seeds from last winter exchanges ( hopefully they are true), and will sow a part this spring, and probably  next year, and so on, in order to have if possible plants from all ages, to compense the monocarpic habit of the species ( I already see so far ).

So place to the stars now!

[ruweiss]

Philippe,
Jim Jermyn describes in his book The Himalayan Garden his experience
with the cultivation of Rheum nobile. Maybe it is useful for you.

[Philippe]

Hi Rudi

That book laid a long time on my nightstand, and I feel it's time to read it once again soon, for all the magic that's inside, for all the superb pics and advices and for all the rest.
I had  it perfectly in mind when I began the Rheum nobile journey with the first plantation in the bed some 3/4 years ago now: cool rootrun amongst rocks, drained mix, and ample humidity. That works pretty well for the moment it seems, but of course this all is made much easier by the mountain climate of the alpine garden.
Another 2 or 3 years without problems, and maybe I would almost find Rheum nobile not particularly difficult to grow here, once its climatic requirements are satisfied. I have far more problems with Ranunculus glacialis that I can never get much further than the simple surviving stage, Campanula cenisia ( which I lost last winter) or Eritrichium nanum for example.
For the moment, there's clearly something much easier and much more peaceful about Rheum nobile cultivation, in regard with all these other plants that yet come from much nearer.
Hopefully this lasts a while!

[Philippe]

Number 1



And number 2



Both Rheum seem now to be in a hurry to produce new leaves. The second one is going on its third leave after only 3 weeks of growth, and the first two leaves were already quite big, for first leaves at least ( 4/5cm length).
They have a complete season now to strenghten a bit more, so come on!

[Maggi Young]

"The high altitude rhubarb from China, Rheum alexandrae flowering at the pond in the rock garden at "The Botanics"  ( Royal Botanic Garden Edinburgh)"

Photo from twitter by John Mitchell

[Susan]

That is absolutely stunning.  Mine has never flowered, just stays quite small - may have to look for another place for it.

Susan

[Philippe]

Beautiful Rheum alexandrae! This is such a presence in the rockbed when the flowering stems are getting higher.
It is also flowering at the Haut Chitelet now.
And the brother nobile nearby is making huuuuge ( in my opinion) leaves right now. Update should follow in the next days

[Philippe]

June update

Hailed Rheum nobile though 
A thunderstorm hit last week-end. Not a disaster, but plants with larger leaves suffered a bit.
So, this means that Rheum nobile now truly deserves the word "larger" for its leaves  New ones will follow anyway.

First plant:



Second one:



It might be not obvious on the pic, but the biggest leave on first plant reaches 20cm, and is hiding almost entirely one Corydalis cashmeriana in the background, which will have to live with an invading neighbour from now on I'm not sure it will get enough light next year if Rheum nobile goes on growing like it does now. Well, pleasant problems, let's say.

A look at Rheum alexandrae just nearby. Encouraging his brother to do the same way one day?

[Lesley Cox]

They're looking very hopeful Philippe. Wonder how long it takes to flower - if it ever does? It will deserve a cake to be baked.

[Philippe]

At least a cake Lesley, at least ...

Despite heat, despite drought, Rheum nobile are healthy





Of course they're watered regularly, and shaded during the days of fierce sunshine, which is almost everyday since 3 weeks now.
But untill now they are admirably withstanding the exceptionnal weather conditions.
Probably the setting helps a lot, planted on the north slope of the bed, where the sun only shines untill 2 or 3 PM, which prevents somehow the overheating of stones around during all day.

Note they were photographed with a wide angle lens, as they don't fit anymore in a more focused lens

[Philippe]

Here a last look at the 2 Rheum nobile.





Number 1 has a worrying look. It grew well untill mid-summer or so, then stopped normal growth, making leaves always smaller as the weeks went by, so that the growing period last leaves are the smallest one of all 
Really don't like the colour of the plants. Would be ok if it looked this way now, but so it was already from mid-august on. Something clearly going wrong with that particular plant.
Maybe a weaker plant that suffered from the tough summer, even though frequently shaded and watered, starting to try to go dormant with the repeated heatwaves, as do some of the more sensitive monsoon himalayan plants?
Because of the colouring of all leaves early in the season and their decreasing size, I fear also a problem at the roots ( rot or anything else reducing the root amount), which could unfortunately be comprimising for the seasons to come. I would not be surprised not to see him shoot again next spring, or really going down next season.

Number 2 is a world apart from number 1. Healthy and numerous large leaves, only the first ones from spring turning yellow now.

[Philippe]

2016 updates!

As expected, Rheum nobile number 1 has given up. No growth this year, how sad.

Number 2 however is still alive and shooting its first new leaves :



The update can"t be that interesting with just one plant, doesn't it?
I hope adding new younger R.nobile to the observations in the seasons to come: some seedling growing in  pots in the propagation area.
But as always, a crucial and difficult stage in the life of Rheum nobile: pot cultivation...
Next stage then will be to check if these are going to be true R.nobile or again R.alexandrae, like last time. For this, it will take several further weeks, untill leaves take more texture/shape and colour to get clues on possible identity. Might also be possible next year only.