Dancing across lacy white cow parsley heads are tiny gnats (don't panic, they're not bite-y) and early hover flies will join them, all to lap up nectar from the many open flowers. Beautiful, native and invertebrate-friendly, cow parsley, Anthriscus sylvestris, is flowering now. Wildly self-seeding, it will happily rush to colonise bare soil to fill any gaps, but in dense planting is rather well-mannered and unlikely to elbow out any neighbours. There is a dark-leaved purple form available, 'Ravenswing' - it is equally colonising. For easy population control, simply cut them down before they seed - if you feel you have too many, the simple carrot-y taproot makes them surprisingly easy to get out (we leave ours in).