I'm compiling a list of trees that can be planted here in Philadelphia to increase forage for our bees. I'm working off a list of trees that the City of Philadelphia (Dept of Parks & Recreation) has approved for planting along the streets.
Some of the choices seem pretty good — for example, Crabapple (Malus), Hawthorn (Crataegus), Eastern Redbud (Cercis canadensis), Serviceberry (Amelanchier), Hackberry (Celtis occidentalis), Tulip trees (Liriodendron tulipifera), and Linden/Basswood (Tilia americana) — in order of increasing size. All the Maples are good, right?
They don't have a lot of really big trees that I recognize as good for the bees, aside from the Lindens which they say can't be planted along the street because they're too big, only in parks, etc. Are Elms good forage?
Other trees I'm not too sure about. I don't want to say that they don't help the bees very much, just because I don't see them listed as good sources. Some are obvious — Ginkgo trees, for example.
Here are some of the trees I don't want to discount too quickly. Any thoughts on these?
- American Hornbeam (Carpinus caroliniana)
- European Hornbeam (Carpinus betulus)
- American Hophornbeam, Ironwood (Ostrya virginiana)
- Honey Locust (Gleditsia triacanthos)
- London Plane, sometimes called Sycamore (Platanus occidentalis)
And what about Oaks?