My garden (where I almost only grow edible things)is almost devoid of colour

Anyway.... long story short.... I nabbed some cuttings / bits of plants.... but all my books (and research of the past 5 years) are about veg and herb growing and I have very little knowledge of these pretty things, beyond how they look... so can I get some pointers please.

Also if any of these plants have practicle purpose I would like to know too

Here's what I have
Bamboo - I know I should be able to coppice canes off of this, which is why I took it really

Lemon Balm - I know it is technically edible, but in what? (I felt a great satisfaction as I identified this even though my mum had no idea... it was left by previous owner)
Pink geraniums
Hydrangea
Aubretia
There might be more... its all still in polybags, I wanted some pointers before I started digging holes....
Any help would be most welcome