lords and Ladies that is such a shame after all the thought and hard work you have put in to attract insects and butterlies. I had that trouble last year and the year before where everything was moreless green untill May. Last Autumn though I planted lots of bulbs which would flower between February until May and by then some of the perenials will have started to kick in. All the bulbs I planted had a benefit or a specific use. This year there is loads of colour and plenty of insects - not many butterflies I must admit but it has made a real difference. I also have a terrace house in a built up area and a small garden (yard) and it only took three years to totally change it for the better, so keep going it will all come together.,
These are the bulbs I planted:-
Chionodoxa, winter aconite, snow drops,Tulips Talpa, Tulips Fusilier, Snakes head fritillaries,Iris reticulata and Crocuses.