Keen to maintain at least the semblance of social utility, a counter to the occasional fatuousness of Lost and Found in E17, the field student of E17 has sought out lists of plants which provide pollen and nectar for bees and alas it seems Forsythia is not among those which will satiate, if that is ever possible, their primal desires.
This list comes from The National Bee Unit
The following flower species are inviting to bees. There are many more:
Comfrey Symphytum spp.
Yellow archangel Galeobdolon luteum
White deadnettle Lamium album
Red deadnettle Lamium purpureum
Sages Salvia spp.
Thymes Thymus spp.
Marjoram Origanum vulgare
Rosemary Rosmarinum officinale
Lavenders Lavendula spp.
Lambs Ears Stachys lanata
Skull Caps Scutellaria spp.
Bugles Ajuga spp.
Geraniums Geranium spp.
Snapdragons Anthirrinum spp.
Toad Flaxes Linum spp.
Sweet Peas Lathyrus spp.
Buddleia Buddleja davidii
Foxglove Digitalis purpurea.
Fruit and vegetable plants which are inviting include:
The importance of trees as a food source cannot be over emphasized. Willows in particular represent a good source of pollen early in the spring.
The British Beekeepers Association has produced a leaflet specifically about trees for bees, from which I will report at a later date.
In, Bees and Honey (George A. Carter, B.Sc., A.R.I.C.) A guide to the better understanding of bees, their diseases, and the Chemistry of Bee-keeping, pub' 1945 - some of the complexities of what makes a plant a good source of pollen/nectar, are described; for instance, the composition of the soil and sub-soil.