I live west of Boston, MA-and we have pretty cold winters. By January, we regularly have sub-freezing night temperatures. A neighbor has planted some eucalyptus trees-these are a variety tha has round leaves. are these trees frost tolerant? Unfotunately, the label doesn’t give the variety names.
I would doubt it. An eucalyptus contains a great deal of water. In a hard freeze it could change into ice and split the tree.
Snow gum? http://apps.kew.org/trees/?page_id=115
There are a fair number of eucalypts that can freeze to the ground and re-sprout from the roots. This can be a good thing since they’re fairly shallowly-rooted trees and can fall over in a high wind. Some people cut them down in the fall and mulch the stumps. That’s what I do, though my climate is milder than yours. I have one of the many round-leaved varieties, but since I bought it for $1 and it was marked only “HERB,” I couldn’t easily tell you which. It gets to 20-30 feet high in a year or two, or it falls over or freezes and re-sprouts in the spring.
Some info on alpine eucalypts to be found here http://22.214.171.124/search?q=cache:fbBoPoYTkmkJ:www.australianalps.environment.gov.au/learn/pubs/vegetation.rtf+eucalypts+that+survive+freezing&cd=13&hl=en&ct=clnk&gl=au
Snowgums survive snow and ice
I have seen Eucalypts growing in Aberdeen, in Scotland (yes, they were snow gums). A tree that can live there can live just about anywhere.
In nearly all of the U.S. you’re going to have a difficult time keeping eucalyptus alive in a tree form.
Even in places with near-tropical climates and frost-resistant varieties, the occasional cold snap will kill mature trees. This supposedly has happened at Disney World, where large trees have been killed off by frost. The problem is that eucalpytus keeps growing late into the season and doesn’t harden off very well. There are climates that stay relatively cool and don’t ever get much under freezing, and certain eucalyptus varieties may survive there, but don’t make it in the U.S. where long stretches of warmth are interrupted by sudden plunges below freezing.
One type of eucalyptus that is sold in garden centers and may survive winter when mulched and resprout from the roots is E. gunnii (cider gum). I’ve had it come back in central Kentucky. The best you’ll get from that is a small shrub, though.
When I lived near Houston I planted a Sydney blue gum (E. saligna) grown from seed. I was back in the area a couple years ago and visited my old place - the gum tree was nearly 30 feet high. No idea if it’s still alive (this part of Texas does have frosts and occasional cold snaps down to the low 20s).
The shape of the leaves may be misleading - some eucalptus species have round, fleshy juvenile leaves, but switch to producing slender, leathery ones when the tree is mature.
Eucalyptus grows like a weed all throughout the Southwest and California. There is a movement to start planting native species in California, because Eucalyptus is so well-established.