There's plenty of the obvious sort of unwelcome plants there - grass, dandelions and such - but our patio had to try to be different! I found sycamore seedlings from the 'helicopters' that fly into the garden in autumn, self-set lamb's lettuce, oregano and lemon balm, strawberry runners, forget-me-nots, dog violets, aquilegias, and even lily of the valley spreading its roots under the slabs!
Most I've tried to remove but some of the flowering 'weeds' I think deserve to stay for a while.
|lily of the valley|
|dog violet and aquilegia|