In article ,
Dave Poole wrote:
The only C. x superba I grow
is "Crimson and Gold" (and perhaps "Geisha Girl") and it is MUCH
less vigorous.

Ah but then you have 'Knaphill Scarlet', Pink Lady and 'Elly Mossel'
which although not necessarily growing taller, are certainly stockier
and heavier growers and once well established, darned fast. ...

So "Crimson and Gold" may be an oddity, though Bean says not.

As to 'Crimson & Gold', at best it seems to be about on a par with the
parents and I've not grown it much above 7 feet except on one
occasion. It spreads sideways with some considerable enthusiasm
though. I think it prefers a really good, rich, moist soil to give
its best and I can't disagree with you on it not quite matching the
speciosa parent.

I have never seen it much above 5', and it has much more of a C. japonica
growth pattern in most cases. Certainly in my garden, where the soil
is pretty good, and in several others I have seen.

As mentioned above Nick, they may not necessarily grow any taller, but
the volume of the plant, thickness of the stems etc seems to be much
greater. Comparing plants that have been established for 8 or 10
years and a good many of the superbas seem to have the sturdier
growth. I suppose it is how you classify vigour - for me height is
only one part of the equation.

Well, the heaviest growth that I have seen (by far) was C. speciosa,
and my C. speciosa has 1"+ stems, very closely packed.

Bean also agrees with me about C. x superba having low, straggling
growth up to about 5' (like "Crimson and Gold") and says that the
same is true of "Knap Hill Scarlet". Possibly, the growth pattern
of the two species/cross depend a lot on conditions.


Regards,
Nick Maclaren.