Planting Sequoiadendron

We get down to a low of about 10F...5F in a very cold winter, but only for a couple of days; our average February would be around 25-30F. Zone: 6a

 

jral - I'm going to disagree a little - it definitely can get colder here on Feb. nites - not necessarily for long, but especially with rocky soil, the rocks can get frigid in there and as it's all solidly frozen up anyway for a long time, I think you're 'wishful thinking' about the tree's chances here. I'd LOVE to be able to encourage you, but unless you're in a known microclimate there, or in.. Yarmouth, I would not be very optimistic.

 

You're probably right; I just seem to recall that just -15C to be our 'cold snap', and yesm I am overly optimistic / (read: determined) to have this survive. I planted one on Wednesday, and another is 'waiting for approval' to go in a city park. On a positive note, sequoiadendron do survive/thrive in colder climates in a few instances.

 

Amending of individual planting holes not beneficial.

Fall best time to plant hardy stock, USDA 6 and above. If you get plants in early, before the roots elongate markedly, establishment is almost immediate: 60% of elongation of roots for entire year occurs in autumn, after overwintering terminal buds are set and send hormones down to root tips. (Being a Cypress Family conifer lacking buds I don't know how Sierra redwood works in this instance, maybe the thicker parts at the tips function as proto-buds).

Total climate determines success, not just winter minimums. Here we see some terminal dieback on Sierra redwoods, presumably from lack of hardening due to cool summers. In nature tree experiences a warm, dry summer and deep, insulating snowfalls.

Sunset National Garden Book zones this tree as far north as southeast shore of Lake Huron, as well as around Lake Ontario (not as far from the water as Peterborough):

"Though native to semiarid mountains of cental California, will tolerate the humid-summer region from southern New England through mid-Atlantic states. Succeeds better in eastern U.S. than Sequoia sempervirens; however, outside its natural habitat, it is subject to fungus diseases that can disfigure or kill it. Prefers deep soils. Requires excellent drainage in hot, humid areas."

 

All of the areas you mentioned are at least zone 6 or better, here we're solidly in zone 5.

 

There are trees in Rochester, NY & others in the Finger Lakes region (of New York). Reports of trees in Michigan, NE Ohio, & I have an old Newspaper article of at least one growing on the Niagara peninsula. If you do a search on Gardenweb, lots of discussion has occured on Giant Sequoia hardiness & if I were to summarize, it seems though above ground portion is hardy to at least -25ºC but the roots require a thick layer of insulating snow as they are sensitive to cold. The trees will do well in the southern Great Lakes, but only in the snowbelt regions. Also, the variety 'Hazel Smith' is hardier than the straight species.

I can't see why Halifax would be a problem, being able to grow large Rhodos & healthy Fargesia (bamboo) with little winterkill? I'd love to be able to garden in NS....Pieris that don't die, English Holly, Umbrella Pine & Cedrus libani all in the Digby/Annapolis Royal region. I suspect there are a lot of gems in Halifax as well.

Simon

 

Down here by the sea, we're 6a:

from the Agriculture Canada Plant Hardiness Zones of Canada:

http://nlwis-snite1.agr.gc.ca/plant00/index.phtml

Geographic:
44° 36' N, 63° 38' W


Data
Halifax, Nova Scotia
Plant Hardiness Zone:
Zone 6a

 

So far so good. Both are doing very well in their new homes and seem to be pretty happy. One is above grade in my yard, (with some bricks around the mound); another is in a very sunny spot in a big city park, in fertile, well drained soil.

 

Note that there is both a Canadian zoning system and a separate USDA zoning system.

 

Yes, the Canadian & US zoning systems are separate, but only in their use of climate data. Zone 5 in both the USDA and Canadian systems is still -20ºF (zone 6 -10ºF, etc.), however the Canadian system uses real Canadian climate data while the US system uses real US climate data and neither uses each other's climate data.

Simon