May in the Northern Hemisphere 2020

[Leucogenes]

...in detail.

[shelagh]

Can anyone tell me what is attacking one of the Hollies?  The pink line round the infected/affected area is natural not drawn by me.

[Gerdk]

Shelag,
It might be Phytomyza ilicis - the holly leaf miner.

Gerd

[Graham Catlow]

This lovely  plant  combination is  from Alan Gardner  in Falkirk
"Japanese maple 'Kinshi' with Rhododendron hybrid 'Winsome' underneath"

(Attachment Link)

Hi Alan,
Great minds!!


Acer ‘Seiryu-vert with Rhododendron ‘Elizabeth’ below.

[shelagh]

Thank you Gerd. I looked it up and it said to leave it as it doesn't do much harm and it's hard to get rid of because Holly leaves are too tough for most insecticides.

[Leena]

When do you think would be the best time to divide Sanguinaria canadensis? I tried it late last autumn, and half of the plants died. I suspect they didn't have enough time to root before winter. Would it be best to divide this clump right after flowering or in early autumn? Or wait for next spring?

In the second picture is nice Anemone nemorosa with dark leaves and lighter blue flowers, and then my "red" A.nemorosa after yesterdays rain.
The last two pictures are of pretty seed grown Primulas. I especially like the first one, it is like painted with water colours.

[Carolyn]

Leena,

I have split sanguinaria  successfully several times. I think I  probably did it as flowering finished, that would seem the logical time, to give the roots time to re-establish before next winter.

[Leena]

Carolyn, thank you!
I will divide that clump then after the flowering is finished. It seems so tight that it needs dividing.

[Maggi Young]

We  wait  until the  foliage  dies  back before  splitting  Sanguinaria.

[Carolyn]

Maggi, Leena,

I thought I would look and see what the RHS advice is on splitting sanguinaria. Under the entry S.  canadensis f multiplex they recommend splitting immediately after flowering. For S. canadensis multiplex 'Plena' they say spring or autumn. So take your pick, Leena! Maybe just do it when you have time, when you remember to do it or even when you are still able to see where the plant is...  I must admit, Maggi's method has  the advantage that you don't have brittle leaves to damage. On the other hand,in your cold climate perhaps it's best to split earlier?  If you have 2 clumps, try each method.

[Leena]

Thanks Maggi and Carolyn.
Last year in the beginning of October was too late. I can't remember exactly when the foliage died, maybe in September.
I have moved Sanguinaria successfully in spring and autumn, but haven't spit it yet. This clump is so tight that roots are on top of each other so it maybe difficult to split.

[Maggi Young]

Leena, if the  clump is  very  congested, perhaps lift  it whole, soak it in water  to allow  any trapped  soil to come  out  and then, having broken the  clump into smaller pieces, ( the broken roots will 'bleed' a bit)plant  them up in quite large  pots ( so there  is  room for  new  root  growth) and  keep the  pots  in a  sheltered position over  winter-  in other  words, treat  the  divisions   rather  like  cuttings needing  extra  protection from the  weather. This way you can prevent the  divisions  facing  too much of the  worst  weather we  know  you can get  in your  garden, and results may be  better   for  you in Spring.

[Rick R.]

I can't remember exactly when the foliage died, maybe in September.

I'm so glad you said this!  I have multiplex for 20 plus years in a mostly shade garden where beech tree roots invade.  They have always behaved like our native Sanguinaria canadensis, dying back as as summer begins.  Climate change has brought me drier springs, wetter summers, and longer falls, and their growth pattern has remained the same.  Ten years ago I moved some to a much sunnier part where Amelanchier roots invade. Here they do better, and leaf retention varies (occasionally into September!), but always at least a month or more longer than the original planting.

I have always transplanted them soon after they die back, simply because they are easier to locate the tubers in the garden. 

[Leena]

I tried to find in last years photos when the leaves died but there were none from that bed taken in August or September. In July pictures the leaves were still in pristine condition. Now that I think about it, also here single S.canadensis leaves die earlier than the double one. I think seeds ripen in early July and leaves die sometime after that. I'll have to keep an eye on them this summer!

Leena, if the  clump is  very  congested, perhaps lift  it whole, soak it in water  to allow  any trapped  soil to come  out  and then, having broken the  clump into smaller pieces, ( the broken roots will 'bleed' a bit)plant  them up in quite large  pots ( so there  is  room for  new  root  growth) and  keep the  pots  in a  sheltered position over  winter-  in other  words, treat  the  divisions   rather  like  cuttings needing  extra  protection from the  weather. This way you can prevent the  divisions  facing  too much of the  worst  weather we  know  you can get  in your  garden, and results may be  better   for  you in Spring.

Maggi, thank you for the good advise. Soaking the clump is a good idea, because it really is very congested. It is a wonder it flowers still so well. I should have planted the divisions in pots last autumn and kept sheltered for the winter, but didn't think about it.

[Gabriela]

When do you think would be the best time to divide Sanguinaria canadensis? I tried it late last autumn, and half of the plants died. I suspect they didn't have enough time to root before winter. Would it be best to divide this clump right after flowering or in early autumn? Or wait for next spring?

In our climate Leena, splitting Sanguinaria is best done after flowering not matter if the regular or the multiplex form. I noticed for all species with large rhizomes that the sooner is done, the better. In years with lots of rain (or very moist garden locations) the foliage remains nice sometimes until Sept. or even October! so it's not a good indicator for splitting.
In particular for Sanguinaria, try to detangle/broke somehow the clump in smaller pieces without damaging them too much; this creates entry points for various fungi.