My potted canna's are growing away strongly in the GH. They are about
9 inches at the moment. I was wondering whether I could put them
outside already ?

I know it's a bit early, but the pots (large!) stand together in a
group and I can always cover them with fleece if it turns a bit iffy.

We live in the inner city (Rotterdam) so it's always a bit warmer than
out in the countryside.

The same question goes for several other frost tender things that are
roping away and taking up too much space..........Tibouchina,
Cordyline, Abutilon, etc

Jenny