There are a couple cultivars of cherry trees, and a fantastic rose bush here on Okinawa I want to bring to America. Since bringing actual plants is forbidden, I'll have to bring seeds.
Rose seeds:
http://scvrs.homestead.com/hybridizekb1.html
Rose cuttings:
http://scvrs.homestead.com/Cuttings1.html
Cherry Blossom Tree seeds:
http://www.thriftyfun.com/tf98116044.tip.html
http://www.ehow.com/how_7415415_grow-cherry-tree-pit.html
Kwanzan Cherry (Japan cultivar) Prunus Serrulata
http://en.wikipedia.org/wiki/Prunus_serrulata
http://cnre.vt.edu/dendro/dendrology/syllabus/factsheet.cfm?ID=310
Cherry Tree Care:
http://www.helpfulgardener.com/phpBB2/viewtopic.php?t=30098
Most of the Washington, D.C. cherry trees are weeping cherry trees, but also a mix of Kwanzan and Yoshino cherry trees. Kwanzan are deeper pink, and Yoshino bloom white to light pink.
