Help for novice please

[GodolphianArabian]

I have potted up some lovely grass plants on my balcony this year. Normally I do flowers but they always die so this year I went for grasses. I am really happy with how great they look. So my question is do I need to do anything with them like prune them or do I just leave them to grow?

Another question about lavender. I have a huge lavender plant in my garden it's over 4 foot tall. I love it. So all my googling suggests I should prune it at the end of August. But that's nearly here and it still looks fabulous and still has loads of flowers and it has loads of bees on it most of the day. So should I still prune it?

Pruning grasses depends on the type. The evergreens, you don’t need to do anything except run your hands through them like a comb to get out any dead stuff. With the others, leave them until spring when you see new shoots, then prune away the deadstuff

For now I would just thin out your lavender and use the flowers in doors. In September cut back hard but not into old wood once the flowers have died. I use my dried lavender in dry displays and they give a lovely perfume even without the flower.

Prune the lavender once the flowers have died - usually August in the S, but mine is never over by August.

In practice it's not critical, and any time up to spring will do (avoid frosty days). I leave mine till spring because the goldfinches like the seeds.