https://phys.org/news/2019-01-cities-key-role-pollinator.html

The research found that residential gardens and allotments (community gardens) are particularly good for pollinators, and lavender, borage, dandelions, thistles, brambles and buttercups are important plant species for pollinators in urban areas.

The team also designed a new measure of management success, based on community robustness, that considers the stability of whole communities of pollinators, and not just individual species. Robustness is a measure of how a community responds to species loss; robust communities can survive the disappearance of some species but species loss in fragile communities leads to a domino effect of other extinctions.