Does anyone grow..

Rhododendron simsii (aka houseplant azalea) outside? I have found they are incredibly hardy considering their description in many books and on labels.

A few years ago, I planted one outside in December, came thought the winter of 2008-9, 2009-10 and although lost its leaves in the winter of 2010-11 came back into full leaf this year and is looking better than it did.

Without doubt this plant is marginally hardy to -10C and I doubt many people will see that in our normal winters. It can also tolerate wet soils and heavy shade but still puts on a great display.

Here's one of mine from a few years ago; the one with the white flowers and pink edges;

 

Must admit I was dubious obout how hardy this plant was Stephen.

But I planted a couple out a few years ago, and they have proved hardy over some very cold winters.

Flowering has not been good for mine though.
Yours looks great.:thumb:

 

I found the problems start if you have a mild start to winter then it gets frosty, it will not flower well. R. simsii naturally flower in winter in their native area, so it will try to flower in winter but often gets halted by frost. If you're fortunate (or have a mild winter) it should flower well in Spring, as per normal Japanese Azaleas. The benefit of R. simsii over Japanese Azaleas is that they don't get those horrible yellow leaves that the Japanese Azaleas get, which is a bonus.

In terms of hardiness; Indian azaleas fulll hardiness -8C I suspect, Japanese evergreen Azaleas; -14C

 

I've planted a few indoor Azaleas in the front garden. One died but two are going strong.

One which I planted last year even weathered the -19C temperatures we had during winter. The other one has been planted out this year so remains to be seen whether it will last until Spring as it's been exceptionally mild so far.