Lavender

Heather grows best in quite acid soil. If the previous owners added peat moss or something around the heather plants to help them grow, that would explain why lavender is struggling - it needs alkaline soil. You should be able to sort out the pH by digging in a bit of garden lime.

I had a similar plan tinaf1. I planted a 12" wide x 9 feet long x 18" deep raised trough all a long the lengthy of my front path and I planted it with nothing but lavender plants. All of them, apart from 2, not only thrived but became so big and bushy that I had to keep chopping them back just so I could get past them. 3 times I replaced the 2 failing plants but they never "took", no matter whether I changed the soil in that part of the trough, or fed them, watered them well/less. I gave up in the end but, like yours, they just looked sickly and grey and never flowered.

Thanks for your replies ,
Geekesse I did wonder if it was because the heather was there first , though that didn’t look very healthy when we removed it. I will try what you have said.

Chewbacca I feel your frustration ? I cannot work out how 5 plants can be put in the ground same place same amount of care and two look so sickly ! I thought Lavender was pretty hardy and low maintenance to grow, did you manage to grow something else in your trough?

tinafl
Have you checked the poorly lavenders for very pretty metalic looking beetles.
This my seem a daft thing to say, but they live in the soil but absolutely wipe out lavenders. Check out Rosemary Beetle.
they can be spotted cling to the plant. If seen, pick it off and squash it!!!!

did you manage to grow something else in your trough?

I did tina! In complete frustration I just bunged a rosemary plant cutting in and it took off like wildfire!

Will be checking for Rosemary beetle bubbly1960,

Looks like you got your revenge on the wimpy lavenders then
Chewbacca not only planted their arch enemy the Rosemary plant but got them to thrive also ?

Morning tinafl. Did you manage to look for the possible Rosemary Beetle? First thing in the morning and late in the evening are good times.

tinafl, do let us know how your garden is getting on, won’t you?

Had a quick look yesterday evening ( we have the builders in at present so bit up in the air) I couldn’t see any beetles will check again when I get up tomorrow
I will geekesse I have held off watering them for a day as I seem to read conflicting reports on how much you need to water Lavender
Thanks for all the suggestions

Re the lavender just to say trimmed it back slightly and it is looking a lot healthier, (hoped I haven’t jinxed it now ?).

Still not as big as the other three plants I put in but keeping my fingers crossed, thanks for all the replies.

We have a lavender hedge and occasionally one bush will die for no apparent reason whilst the others around it carry on growing. I'll check them again, but have never noticed any beetles.

We found the best type is Hidcote, it is upright and stays neat and tidy. We bought another 12 Hidcote bushes and planted them but they have turned out to be another type altogether, sprawling and untidy.