Polygonatum stenanthum - update for Ben and Chad perhaps?

[MartinNicklin]

I managed to get hold of this after seeing it featured ar Chelsea a few years ago and lusting after it. It grew well and flowered nicely with its very large bells but last year the growing points were eaten (I assume by a rodent as they were snapped off and gone) so I dug up and potted the rhizome. Nothing has appeared yet but I was just looking it up in case I need to replace it. It is quite hard to find and not offered by my original source but Crug have it now listed as macranthum. Has its name changed?

[Chad]

Oh Dear!

Polygonatum is under constant review and Crûg have The National Collection.  They may often be ahead of Kew with new names, but this isn't one of those occasions.

The plant material previously ascribed to Polygonatum stenanthum has been re-appraised as belonging to Polygonatum macranthum.

But...

The actual Polygonatum stenanthum, which Crûg didn't have, wasn't a 'good' species anyway and was probably Polygonatum falcatum var. falcatum.  But that wasn't the plant material that Crûg actually had, so it didn't really matter.

And don't get me started on the 'red kingianum' which I'm calling Polygonatum huanum until someone I trust tells me otherwise. 


Chad

[Chad]

It is a bit early to be writing off Polygonatum as a no show. Even in Cornwall I only have the precocious P.vietnamicum showing, that is already in flower. If there is any firm rhizome in the pot it should resprout, even if it misses a year.

It is disconcerting that they don't resprout 'out of season' and wait until the next year to show.

Chad

ps. The large flowers probably make the one you have attributable to Polygonatum macranthum.

[BenC]

Hi Martin,

As Chad rightly points out, Polygonatum stenanthum is a synonym of Polygonatum falcatum. Plants that had been circulating under the name of Polygonatum stenanthum are in fact invariably Polygonatum macranthum.

So, if you're looking for a replacement, try sourcing P.macranthum and it will likely be the plant you're looking for. Possibly.... :lol:

I also wouldn't worry about a 'no-show' at this time of year. I have many species here grown as potted specimens, and only a few are showing above soil level. None to be seen in the open garden yet (although I can only really grow a selection of the verticillate species in the ground due to slug, snail and sawfly problems!

[MartinNicklin]

Thank you for these useful replies. I’m hoping it will re-emerge this spring. If not, I see Crug are selling it as a last resort.

Just checked and there is growth … but only one shoot as yet.



So my next question: how long does this plant take to bulk up?

[Chad]

Sorry, I didn't spot your amended post at the time.

Bulking up Polygonatum is all about making a bigger rhizome for the next year.  It is frustrating that you can't tell if you are winning until the next year.

Keep it well fed and well watered to try to prolong its season of having green leaves.  If you have sawfly larvae, pick them off assiduously.

I over pot mine, putting a second year seedling into a 15L pot. They flower usually in their second year from seed, if pampered through the first year, but often only have one stem.

If all goes well there are half a dozen stems in the third year.  Or still one stem if I left them in a small pot, unfed and a bit neglected!

Chad

[MartinNicklin]

Thank you Chad. I covered the pot (I think it’s about 10L) with a tall polythene bag, primarily to stop whatever ate the new shoots last year from doing so again. I assume it was rodents as there was no slime and nothing left behind in terms of evidence. Since covering it, I noticed another nice fat new shoot emerging, bigger than the one in the photo, so there will be at least two! I grow polygonatum and disporum and haven’t had, as far as I know, sawfly. I assume whilst the tender shoots are pushing up, the bag will offer protection against this?
It did flower the second year I had it. Lovely big plump flowers, quite distinct from other forms. I seem to remember posting pictures on GOTE. I was so enamoured with it, hoping that the clump would expand, that I was bitterly disappointed last year when the long awaited shoots were devoured and I was left with nothing for the rest of the year. In that respect I am very pleased to see it return, not least because it’s not that easy to get hold of.




So this is the plant I was originally wowed by, said to be stenanthum. Is it macranthum or falcatum?

[Chad]

You've done it again, haven't you? Edited a post so it doesn't move up the list and then not had a reply because no one saw the edit.

And I don't know the genus well enough to answer the question anyway.

Sorry.

Chad

[BenC]

Hi Martin,

Sorry, I had also missed your updated thread (I don't look look in on this forum as much as I'd like due to time constraints!)

The plant in your photo looks to be P.macranthum: the more upright habit and size compared to P.falcatum, number, size and shape of flowers, leaf arrangement and texture all point to that.

If you've got a few hours to spare, you can wade through this long thread from the SRGC: https://www.srgc.org.uk/forum/index.php?topic=2033.0
There are some useful photos of P.macranthum on page 6 of that thread, and lots of info from some of the experts in the genus. If you're on Facebook there is a good group called 'Polygonatum, Smilacina and relatives Enthusiasts' which is worth joining if you're keen to know more about these genera and related plants. The trouble with that group is that it's part of FB, which I hate!

[MartinNicklin]

Thanks so much Ben. That was very interesting so thanks for taking the time and effort to post that. Looking at the flowers on the illustrated macranthum, I can’t swear to it (and unfortunately we can’t retrieve photos from GOTE where I posted one), my flowers seemed to be more balloon or lantern-shaped, though still impressively large. Hopefully, I’ll get flowers this year to update this thread.
Incidentally, that nodosum red leaf form is stunning!
I was on FB but came off it, fearing that some posts would tempt me to respond with rants!