What's Wrong With My Euphorbias?

I've had these two Euphorbias for almost three years and then in the summer both of them suddenly dropped most of their leaves. I cut back the dead leaves in an attempt to save them and some new growth has returned but it's not as vigorous as the last few years.

Here's a photo of one of the affected plants. Where this plant in has changed recently as I had a new shed installed and the grasses seem to block out a lot of the light to the plant now.



Any suggestions on what to do would be greatly appreciated.

 

No idea, Jane, but hopefully you'll get the advice you need to save them.

 

The soil looks very dry, could it be lack of water?

 

I have started to give them more water with the can. But some reason I thought Euphorbias liked dry soil.?

 

With the shed now close to them JJ it may be preventing rain from getting to them properly, it hasn't helped with the dry summer we've had. It might also help to give them a one off liquid feed as well to give them a kick start.