Dichroa (now Hydrangea) hardiness

[NigelJ]

I have Dichroa febrifuga, D "Long March" and D daimingshanensis Guiz 48 growing in the ground at the side of the house in Paington , been there since 2023.
Just wondering about hardiness, D febrifuga RHS have as H3, but Burncoose say cool greenhouse overwinter and D "Long March" as a conservatory plant.
Trees and Shrubs Online have D "Long March" as H3 and D febrifuga as H4.
Does anybody else on here grow these and what have you found there hardiness to be.

[Chad]

I think the lack of replies suggests they aren't widely grown. 

I don't have any.

I asked John about them. They aren't on his index, but he said that he has had Hydrangea febrifuga out for three winters [not bad ones] without damage. 

Hydrangea × versicolor he has had for longer and it was cut to the ground in a bad winter, but grew back strongly. 

He suggests that since they are so easy from cuttings, plant them out but keep some cuttings under cover until you are happy they are hardy with you. 

Chad 

[NigelJ]

Thank you Chad; I shall do as suggested and take cuttings.

[BenC]

Hi Nigel, I can't offer any more advice than Chad has already given. But H.febrifuga is growing well at Killerton, and has been for a long time. The gardens are in a frost pocket and can get several degrees colder than winters in your more coastal location. It is planted in shade and on a slope in the rock garden area, so perhaps the worst of the cold air drains away a bit. But I imagine it does see a fair bit of frost.

A back up cutting or two might be wise but I'm pretty sure this one will be ok for you. No idea on the others you mention though.

Hydrangea febrifuga by bcandlin, on Flickr

[NigelJ]

Thank you Ben, that's useful to know about H febrifuga growing at Killerton. Almost certainly colder than me, my main problems come from Easterly breezes in spring desiccating young growth.
My H febrifuga "Cambridge Blue" is more "Cambridge Pink" the other two 10 yards away are good blues.