These 'boos have a similar mature size/culm diameter. P. decora is reportedly a little more cold hardy. I'm interested in trying them in zone 6a WNY. Does anyone in a zone 6 with long cold(cold = below 20F for three months straight w/single digits common) winters have experience growing these two species? I can just try and see how they perform for me, but thought I'd ask if anyone else has experience first. Thanks!

The Dulcis will produce fewer, but fatter culms, I'm seeing a tad over 1.5 inch diameter at around 16-17 feet in height, Decora will produce lots more shoots but thinner and taller canes, around an inch plus by 18-20 feet tall.

Temp ratings are deceptive at best, if temps STAYED below +20F continually for 3 months, then I'd throw out the temp ratings and expect lots of damage.

My post lists damages caused by periodic arctic blasts that can happen each year at those temps I listed which generally cause the damage as I described. Such is why I avoid temp ratings on my website, they do not tell the whole story.

Here's a better explanation of my winter temps:
avg. min. temp. = -5F
avg. #days below 0F = 4 (at least 1 per winter)
Temp's hover between 20F and 32F for most of December. January and early February see temperatures rarely above 25F. During this time period, we usually have up to a week at a time where temperatures STAY in the teens to single digits fahrenheit with a day or two of 0F or below. During the end of february and early march, temps hover again in the 20 to 32F range. So, it would be more accurate to say roughly 1.5 to 2 months of temps that consistently STAY below 25F with periods consisting of consecutive days with temps below 15 to 20F.

Like you said, temperature ratings aren't everything. I'm in zone 6a based on avg. winter minimum. However, it gets cold and stays cold for a long time here. Cold hardiness of plants should not be based on the lowest temperature they can survive brief exposure to but a temperature that they can survive prolonged exposure to. I look at a plant rated to zone 6 and think "if it stays between -5F and +5F (ignoring wind/exposure effects) for a month straight, that plant will be in perfect health come spring". Very misleading.

If you already have these and are adding either the Dulcis or Decora, the Decora will likely hold up a tad better in your winters - but not as good as the above. Your long stretch of below freezing high temps will likely result in cane damage most years and hold mature sizes down - wind is the real enemy and frozen ground plus wind you'll get damage similar to serious subzero.

I currently have:
P. rubromarginata
P. atrovaginata
P. aureosulcata
P. aureosulcata 'spectabilis'
P. nuda
P. nigra 'henon'

So far P. nigra 'henon' has gotten the tallest, P. rubro. sends up the most canes each year, and the others have the best cane survival percentage. Mine are growing in a very exposed location, so I get a lot of top die back on all of them. You can check out this thread for more detailed info about my experience with these species:

I just wanted to add either P. decora or dulcis to my growing collection and was curious as to which would do better for me. There's a 20-25' grove down the road from me, so I know they'll survive long term. I'd be happy with 15 to 20 foot canes on any of my 'boos someday . . .

That is based on what I see here anyway, it is always different in different places.

I like the idea of fatter canes at the expense of a fwe feet of height. However, I probably won't see decent height on dulcis because of die-back, making me think I should go with decora. Thanks for the input!