On 29/08/2013 20:43, Roger Tonkin wrote:
I have a number of dahlia tubers, all from the same
source (as do many people round here!. We divide them
regularly and share them around, or sell them at
church coffee mornings).

This year, I planted some in the back garden, south
facing and near the house, so quite warm, and some in
the front, much cooler and no sun from 10am to 5pm.

After the usual battle with slugs, all have grown
strongly and one flower opened in the back first.
Front have now started flowering well, but in the
back, although there are lots of buds, the flowers are
not opening, just swelling very slowly.

I admit that they have been planted in the same bed
for the last few years, but I've never had this
trouble before.

Any ideas as the possible causes, plants all look
healthy and same as the ones in the front.


It is just one of those years.
I'm hearing the same thing from dahlias growers around the USA short
plants, plants just not flowering or being very slow, some are saying to
wet, others not enough rain whilst others are blaming temp. My dahlias
are very patchy, the first ones I got in are blooming well, but the ones
that were just a week or 2 or 3 or 4 are very far behind, they were
planted when we had the heatwave, but also they were transplanted into 8
inch post plunged into the ground, to add to the problems I am using a
compost that's around 50% coir, so probably quite acid and low on fed
though they have had a diluted feed every watering, which during the
heatwave was every 3 days.
The idea is that the feeder roots would grow out of the bottom of the
pots and the tubers would be retained in the post.