× Chiranthofremontia is an intergeneric hybrid of our native Fremontodendron and the Mexican genus Chiranthodendron. Both belong to the mallow family, Malvaceae. Intergeneric hyrbids are rare, both in nature and in cultivation, as it is rare to find two different genuses that are genetically and physically compatible enough to produce offspring together. The specific hybrid I have seen locally is × Chiranthofremontia lenzii which is also the only one to exist as far as I know. This plant is a hybrid between Chiranthodendron pentadatylon and Fremontodendron 'Pacific Sunset', which is itself a cross between Fremontodendron californium and F. mexicanum. Quite a diverse family tree! How many of us can say we have grandparents that belong to three different species?
As is typical with hybrids, this tree is midway between its parents. The ones I have seen have a strange intermediate form as might be expected of a hybrid where one parent is a tree and the other a shrub. The orange flowers are attractive and have a fairly long bloom period. It's not totally clear what the environmental tolerances of this tree are, but it's clearly hardy here, so perhaps it should be trialed in more locations. Like both of its parents, it reportedly does best in well-drained soils, but I'm not sure it has been trialed enough to say exactly how picky it is about this.
As is typical with hybrids, this tree is midway between its parents. The ones I have seen have a strange intermediate form as might be expected of a hybrid where one parent is a tree and the other a shrub. The orange flowers are attractive and have a fairly long bloom period. It's not totally clear what the environmental tolerances of this tree are, but it's clearly hardy here, so perhaps it should be trialed in more locations. Like both of its parents, it reportedly does best in well-drained soils, but I'm not sure it has been trialed enough to say exactly how picky it is about this.