Are delphiniums hungry?

I have been watering my whole flower bed with miracle grow since easrly spring, once a fortnight as directed.
My delphiniums haven't produced many flowers though :confused:
Everything else is going great guns and the flowers it has produced are nice, there just aren't many of them.
Here's a picture.
My dad says they need a stronger food. Is this right?

 

Anyone? Someone must grow delphiniums surely?

 

I suspect they might be a bit close to that fence, it could be keeping some of the rain off.
I transplanted some of my father in laws delphiniums cause they were where i wanted to grow vegetables. I stuck some manure under where they were going to be planted. They are about 7 feet tall and full of flower. I think they like a lot of organic material, not just fertiliser.

 

I just use general fertiliser on mine once a year before they start to grow. They seem to like a drink and the ones in the drier area are less prolific for me.
Plants are funny things some grow well where the 'Gardeners' tell you they should not and others.............etc. One of the reasons that I keep interested in gardening - what you really need is some of that special soil that they have on Gardeners World where everything grows well............

 

All mine have been eaten by slugs so don't think I'll get any flowers this year either!

 

Mel, so have mine. I grew them in tubs until they were quite big plants and planted them out in their 3rd spring. They flowered nicely last year but this year despite all I could do to protect them all have gradually been eaten. I have 2 stumps left
I ned to get them big enough to form nice fat clumps that can withstand attack.

 

I just have stumps left too.Soooo annoying!! they were doing really well in pots in the greenhouse and once I planted them out they lasted 24 hours before being devoured completely!

 

Thanks everytone. I'll try some manure on the next spring then.