Hi David,

I have Acer x ‘Cinnamon Flake‘, which is a cross of A. griseum with A. maximowiczianum. Don’t know if they will cross with A. japonicum.

.Apparently they can hybridize with several different Acer species:

A. saccharum

A. nickoense/maximowiczianum

A. triflorum

A. pseudoplatanus

There is nothing in the literature to indicate they would cross or have been crossed with palmatum, japonicum, shirasawanum or circinatum.

Acer griseum is known to have issues with seed viability. Either seed production is quite low (that as not been my experience) or the vitality or ability of the seed itself to germinate is questionable.

Thanks. A. pseudoplatanus is a common weed tree around here, so if it is an outcross, that seems the most likely.

Well, I learned something today. I've always thought maples could only cross with other species within the series. In this case it would be Section Trifoliata, Series Grisea, which includes A. griseum, A. maximowiczianum, and A. triflorum. A. mandschuricum, which is also a trifoliate, is in Series Mandschurica and would not naturally hybridize.

David, maybe you've got something this in your garden.