Aesculus Species, Conker Tree, Horse Chestnut

One of these entries says it's flowering in Zone 9b. Plantfiles officially limits it to a maximum of 6b. Shouldn't the range report be modified ?

This European species is occasionally planted in parks and some residences in the Chicago, IL, area and other parts of the Midwest. Some ...Read Morelarger conventional nurseries some sell this, as Hinsdale Nursery. It does well there. It does get hit harder by the buckeye leaf blotch disease that shows up in late summer than do native buckeyes, and it can get leaf burn from hot, dry, windy summer weather. Its large flower clusters are mostly white and its spiny capsules and brown seed are larger than that of buckeyes, as are its large 7 leaflet compound leaves. I saw a huge abundance of this species planted in western Europe in the 1980's.

There are a couple of mature ones growing in Edmonton, AB zone 3a/b that I know of. One downtown has been there for decades and its abou...Read Moret 40 feet tall. Beautiful tree that looks like an Ohio buckeye with nice spring flowers.

Very uncommon tree species here in the Twin Cities - I have only seen them in tree collections but recently I saw some planted along a st...Read Morereet - their distinct white flowering gives them away plus their leaves look like buckeyes but they are not as sensitive as buckeyes. Do anyone know why they are rare?
Their seeds are poisonous and also they grows bigger and taller than buckeyes. I have seen one at St. Cathrine Campus - St. Paul also seem to be decades old - makes one wonder why there was a trend of growing them in the past and then stopped selling them?