Best of the Hardiest

Have you ever had to choose between several attractive cultivars of one plant, and wished you knew which one was the hardiest? Me, too. That’s why I’ve created this page. Every time I find out about the hardiest cultivar or species of a plant, I’ll put the information here. I expect lots of help from the reading public here! You don’t have to have grown it yourself if you can cite your source of information. (This was originally called Name That Plant!)

Botanical Name Common Name Hardy to zone Source/Comments
Arisaema amurense subsp robustum, green form none–it’s an Asian relative of Jack-in-the-Pulpit 3 Original source out of business. However, while it makes it through the winter in my garden, it emerges too early and I have to protect it from early frosts.
Caryopteris X clandonensis ‘Arthur Simmonds’ 5 Forestfarm
Cotinus coggyria ‘Nordine Red’ ‘Nordine Red’ purple-leaved smokebush 5 “I have planted Cotinus in several locations and
have planted both Purple Smoke Bush varieties. I have found that
all may die back to ground in harsh winters and ‘Nordine’ is weaker
than the standard form. The nice thing about the dieback is that
new growth always has more brilliant leaf color. There probably
won’t be any flowers but I grow it for the foliage anyway. By the
way, we have one huge Cotinus in Oneonta in the yard of the public
library (not purple) that looks like a spot of fog in the lawn when
it is in full bloom. Spectacular.”–Penny K.

See also my experience here.
I can’t seem to find my notes that indicate what gave me the notion
that it was hardier than the others (maybe Dirr?), but several sources
on the internet echo this idea.–Kathy

Clematis ‘Prairie Traveller’s Joy’ 1 “I have been growing this ironclad hardy huge (15′
tall ) white clematis in Edmonton, Alberta for years now. The late
summer blooms are the size of a quarter, and have a lovely light almondy
scent. …You can also easily take shoots from the bottom for new
plants.”–Pamela M.

Source: Rundle
Wood Gardens