Agree lavender but I'd just go with hidcote the plants seem more compact than munstead.
Just want to say thanks to Notaclue for raising this subject and to all who responded. We have just completed a build project and have a south facing 20 meter retaining wall, we've created a flower bed on top of the wall and have a white picket fence behind, our raised lawn is beyond. A lavender hedge came to our minds too, I've spent a little while researching the different types to select the most suitable to give us flower longevity & had a little wonder about how it would look once flowering is finished. I have therefore found this thread really useful - thanks again to all.
I have planted, earlier this year, a lavender border hedge of alternate Hidcot and Munstead. Flowering already but and am very pleased with it. Can't wait fro it to fill out
Here is mine, think it's Munstead, but may be Hidcote.
Does anyone know, are there two types of hidcote lavender.? I bought a lavender labelled" giant hidcote," from Kiftsgate, which is of course the garden the other side of the road to Hidcote.It is a lot larger than Munstead. The flower spikes are about 2 ft long. I keep trying to propagate it, but there is a distinct lack of suitable material , as every shoot has a flower. It is still in tight bud at the moment. Munstead is already flowering. All the plugs I got as part of the gardeners world offer, are certainly seed grown, which to me means they cannot be true to name, since the named variety should only be propagated by cuttings.
Fidgetbones, found you this: http://everything-lavender.com/lavender-hidcote.html
Just scroll down a bit, and you'll find the answer.
It appears to be named correctly then. It has huge spikes. Thanks flowerchild.