The following are a few native wild fruits which, some of which I currently have:
Wild plums(Prunus: American plum, beach plum); wild cherries (Prunus: pin cherry, black cherry); currants (Ribes: American black currant, eastern prickly gooseberry); chokeberries (Photinia/Aronia spp.); American mountain ash (Sorbus americana); hawthorns (Crataegus); Walnut family: Juglans spp. & Carya spp.; and a variety of blueberry species (Vaccinium spp.) and raspberries/blackberries (Rubus spp.). Additionally, are edibles like native garlics (Allium spp.)& mints (Mentha spp.).
I know that certain natives like red mulberry (Morus rubra) and hazelnut species (i.e. Corylus americana & C. cornuta) will readily hybridize with non-native types with like-chromosome counts - M. rubra with M. alba; C. americana with C. cornuta (both native) and both of these with the European species, etc.
Yet, even with like-chromosome counts, in some pairing situations, inter-specific hybridization will not occue without the guidance of human intervention. For instance: Diospyros virginiana, D. rhombifolia, and D. lotus have each 90-chromosomes, but they cannot readily polinate each other - and this has nothing to do with timing.
Lastly, I know that in some instances, open-pollination will result in infertile offspring, such as with Vaccinium vitis-idaea spp. minus vs. the European version of ligonberry.
So, hopefully someone can let me know which of the following pairings will produce inter-specific chance hybrids:
Native vs. Non-native;
1. Grayleaf raspberry (R. ideaus spp. strigosus) vs.
European common raspberry (R. ideaus spp. ideaus)?
2. The various American blackberries vs. the various European blackberries and native/non-native forced hybrids?
3. The various native plums with Prunus domestica or P. tomentosa (I think I read that P. tomentosa (Nanking cherry) will freely hybridize with P. pumilla (sandcherry)?
4. The various native crabapples with Malus domestica/pumilla?
5. American mountain ash with European or Asian pear, or the quinces, or at least with European mountain ash? Same for chokecherries since, I think I remember, that Pytina/Aronia can hybridize with Sorbus americana.
6. The various native plums with the man-made plum hybrids?
7. The native plums with peach/nectarine or almond?
8. The native mints and onions with the European garden species.
9. The native silverberries with non-native Eleagnus spp. (Russian olive, Autumn olive, goumi).
10. The native honeysuckles (Lonicera spp.) with the increasingly popular blue honeyberry/haskap (Lonicera k... forgot).
AND NATIVE VS NATIVE:
1. Forb/herbs like the Agastache spp. within themselves, the Monarda spp. within them selves, and so on. It seems that there are not many natural intermediaries between species in the same region - yet, maybe which mixing members of a genus that are regionally exclusive of each other, the likelihood for chance hybridization is greater?
For instance, are the various Rhododendron spp. of a given area unlikely to hybridize with each other and same of the blueberries of a sub-region, yet when you plant Rhododendron spp. and, respectively, blueberries with their cousin species from opposite coasts, will hybridization occur more frequently?
I which that there were an online resource cataloging natural compatibilities within familiar horticulture genus.
Purpose: I don't want to plant any foreign plant near my natives that would be cross-fertile. I would plant Prunus tomentosa if only it wouldn't supposedly readily hybridize with P. bessyi.