We have large areas of scrub in our 'wildlife garden' and things like bramble have pollinators on them from the first blossom in spring and then in autumn all manner of invertebrates feeding off the over-ripe fruit. Elsewhere in the rough grass we have knapweed which attracts butterflies throughout its long flowering season.
However, you probably don't want bramble and knapweed in a garden
- so we have marjoram and cat mint around the house and they are covered in butterflies, bees, hoverflies and more. We also have an escallonia against a wall that is a real draw to Red Admiral and a berberis darwinni that is covered in bumble bees early in the year. The latter two, being shrubs, you will have to prune to keep the height down eventually.
Gatekeeper on Bramble
Common Blue on Knapweed
Small Tortoiseshell on Marjoram
Red Admiral on Escallonia