David Fenwick Snr.
Thu, 24 Jun 2010 17:42:37 PDT
>>>>>Crocosmia paniculata has grown and multiplied for me outdoors though it
hasn't bloomed for a while.  I think this was due to dry soil and
excessive crowding: a quite wet spring and greater breathing space may
do the trick.

Absolutely correct. This is the reason why ALL Crocosmia stop flowering; for 
as the corms multiply they push up and colonies become thicker. Soil dries 
out the closer you get to the surface, and more corms mean more competition 
for water and nutrients, which of course the corms don't get, and they don't 
get to grow to a flowering size, and may stop flowering. This is why it is 
suggested they clumps are lifted, divided and replanted every three or four 

The more vigorous the variety the more this is a problem. However, this can 
obviously be overcome initially by providing more feed and water during the 
growing season; the clumps will still need to be divided at some point 
though. I found this also to be the case with larger Watsonia. I had some 
success with these at planting 15 inches deep, at this depth they multiplied 
slower, but this kept the corms cooler and moister during the summer, and I 
had really good flowering clumps which never stopped flowering. Only large 
established pot fulls were planted at this depth.

The long stacks / chains of corms are actually food stores so if planting 
out in the ground most corms will fair better if a few more older corms are 
retained. Most people who sell corms though, 'fresh dug', rather than 'dry' 
corms, only send with the first one or two corms usually because of the 
weight the extra corms will but on the postage. There is also a greater risk 
of spreading diseases such as rots by sending older corms, which are more 
prone to rotting. New corms primarily do better in pots primarily because of 
media, they'll produce a better root system and will probably get more feed 
and water than if planted straight into open ground.

I never had any success with Chasmanthe bicolor outside until I planted 50 
corms in a pit a foot wide. This species, a Crocosmia relation, and isn't 
perfectly hardy in the UK; but this shows how important it is to plant 
mature corms and large groups to obtain hardiness. These corms were also 
planted under a large shrub to afford a little more frost protection also.

Best Wishes,

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