My A. Oblongum is in a pot and is getting too big to move in and out of the greenhouse, when frosts are forecasted. Thus, I want to plant it in the ground and I would appreciated any feedback on hardiness. Zone 7 and below seem to be clearly forbidden and zone 9 and above are OK. Zone 8, where I am, is borderline. Who is growing this maple and where?. The UK is almost all zone 8, I would assume that some valuable experience must exist there. Gomero
One specimen has had a long residence at the Seattle arboretum. Sometimes it is hurt by cold, do not know current status.
The interactive map at Westonbirt lists three specimens but all are young (Sizes given 0m, 1m and 1m, the last two var. itoanum), and obviously no guarantee they are actually still there. (I couldn't find their specimen of Acer pentaphylum last October, for example, but don't know whether that means it is dead or just that my navigational and map-reading skills are far worse than I thought.)
Your maple is a seeding or grafting? Its not the same from culture in the garden, i had one grafted on Pseudoplatanus, he died but the understock is alive, winter -12/-15 °C. Another one that is grafted on Buergerianum grow in greenhouse very well, planted on pot and have leafs throughout the year. I'm afraid to put in the garden.
Seattle is a bit colder than Toulouse, this is a useful hint, thanks Ron. Hmmm, very suspicious Maf, bet you they are replacement for deceased trees. It is a seedling. Lyon is in zone 7 so I would not advice planting it in the ground in your area. Gomero
I know that Masayoshi Yano (Autor of 'The book for Maple) grow some Acer Oblongum, he say that Oblongum var Itoanum seems most hardy. He has one big Oblongum in the garden, he lives in Utano near Osaka, i don't know the number of zone but he has often lot of snow and cold. i search a photo in my archives! Acer Oblongum
Utano is in the Nara Prefecture and the whole area is zone 9 (with very heavy rainfall, between 3000 and 5000 mm or 120-200"), which is ideal for A. oblongum. Gomero
i have one,in zone 9 ,winter 2010 is was with snow and low temperature for many days,the oblongum is in good health,i presume that is important the pine bark around the trunk , for protection root system.
