that's usually due to lack of water as the buds form and or frost in the early stage of bud development.
How newly planted are they? I give any new ones lots of extra water as soon as they start showing growth to get them to 'plump' up. unless its excessively wet. I find the lactiflora type do this more than the officinalis type.
do you know which it is you are growing?

I sympathise, My peony puts on lush growth every year, but has only flowered once. That was 20 years ago when we first planted it.

They are also gross feeders so give them plenty of Tomato fertiliser now and a good general one when they first appear.

Thank you Owdboggy, I will do that x Nan

When new peonies are planted the most common, and serious, mistake is to plant them too deeply. Peonies need very shallow planting. if planted too deeply they can take years to flower. Very shallow plant for success.

Yes i agree with john58, this is the more likely cause of poor flowering along with being to dry.

Many thanks to you all for your good advice. The plants are about 4 years old and have never actually flowered just getting buds as previously said. I shall definitely try watering and feeding because I don't actually do either of these unless it is very dry and then I water the whole garden.

By the way, if anyone has problems with growing heucheras - I find that mine do so much better when they have a lot of water. If we get a very wet summer like last year, then they grow really well.

Thanks again for the help.