under hedge

I don't know the answer for sure, but my understanding is that leylandii are quite hungry plants and it may be difficult to get anything to grow too close - plus being evergreen, they don't have the advantage of letting the light in over winter and spring which would benefit flowering plants of that season. As I often say, more knowledgable people than me will advise you better. How big is your hedge, by the way?

You will probably find that the area under your hedge is riddled with roots and it will also be seriously dry and under-nourished. Not a lot will be happy in that situation. You could make a flowerbed further into your garden - still in their shade - for your Hellebores etc.

I think I would put in raised bed's. I hope those Lelandi dont get too big, we cut our's all down as the people at the bottom of the garden missed out on sun & light.x

Hello
I had a leylandii where I lived before I moved last year and I
grew some lovely mauve periwinkle under and it took off very well its worth a try it was looking lovely just before we moved