9b Zone Palm Hardiness Data (from Palmpedia)

[Hillizard]

FYI from Palmpedia: 9b Zone Palm Hardiness Data
"Special thanks to member John Case. John pushes the envelope with palms just about as far as possible in Inland Northern California."

"'This is a list of palms that a person might consider when living in Eastern Contra Costa County in Northern California. It is a 9b zone with cold dry winters, rainy season from late October to March, and hot dry summers with extended periods of over 100 degrees.'"

https://www.palmpedia.net/wiki/images/4/4a/Book1East_County_Palm_Index.pdf

[fr8train]

What is the minimum temperature listed there based off of? I'm just surprised by some of those numbers, unless I'm not understanding something correctly.

Like:

Trachycarpus wagnerianus 20F vs Trachycarpus fortunei 5F

Phoenix canariensis 20F vs Phoenix dactylifera 15F vs Phoenix theophrasti 5F

From what I've read about and seen in Texas, Phoenix canariensis is by far the hardiest. 

Edited November 29, 2023 by fr8train

[Hillizard]

41 minutes ago, fr8train said:

What is the minimum temperature listed there based off of? I'm just surprised by some of those numbers, unless I'm not understanding something correctly.

Like:

Trachycarpus wagnerianus 20F vs Trachycarpus fortunei 5F

Phoenix canariensis 20F vs Phoenix dactylifera 15F vs Phoenix theophrasti 5F

From what I've read about and seen in Texas, Phoenix canariensis is by far the hardiest. 

Wish I could answer your question about minimum temperature, but the information I posted was all that was offered. As most of us have learned, sometimes, despite the zone a palm is being grown in, it's the particular microclimate in which it's planted that can make the difference between success and failure. And with climate change, that's getting more challenging to predict. 🤔 Here's a link to some follow up info that explains how he compiled the list: https://forum.palmpedia.com/threads/east-contra-costa-county-palm-list.351/#post-4089

[Than]

Dry winters but rainy season from October to March? 

Also I believe the existence or not of frost should be mentioned. I have realized that frost kills more than dry cold does.

[Dwarf Fan]

On 11/29/2023 at 5:46 PM, fr8train said:

What is the minimum temperature listed there based off of? I'm just surprised by some of those numbers, unless I'm not understanding something correctly.

Like:

Trachycarpus wagnerianus 20F vs Trachycarpus fortunei 5F

Phoenix canariensis 20F vs Phoenix dactylifera 15F vs Phoenix theophrasti 5F

From what I've read about and seen in Texas, Phoenix canariensis is by far the hardiest. 

^^^ Yea once you factor in Microclimates, frost, wet, advective, South facing, building protected and let’s not forget variable cold tolerance genetics, it all points towards there never really being a hard number for most species!

I will download it and add it to my other “expert” compiled cold Hardy list below. However, the sheer number of dead Phoenix roebelenii on my street alone (forget the entire Island LOL!) tells me that P. roebelenii is definitely NOT a 20F Palm

This guy seems really overly optimistic on many, many species and even whole genuses, according to his list I can grow Dypsis… really Dypsis?

“Syagrus romanzoffiana 10F”… 🙄

Also, at this point my own personal list has much better Palms that are more rare and exotic, heck the sheer number of possibilities with cold Hardy hybrids alone is staggering and would make for a massive “list”.

 

[SeanK]

2 hours ago, Dwarf Fan said:

^^^ Yea once you factor in Microclimates, frost, wet, advective, South facing, building protected and let’s not forget variable cold tolerance genetics, it all points towards there never really being a hard number for most species!

I will download it and add it to my other “expert” compiled cold Hardy list below. However, the sheer number of dead Phoenix roebelenii on my street alone (forget the entire Island LOL!) tells me that P. roebelenii is definitely NOT a 20F Palm

This guy seems really overly optimistic on many, many species and even whole genuses, according to his list I can grow Dypsis… really Dypsis?

“Syagrus romanzoffiana 10F”… 🙄

Also, at this point my own personal list has much better Palms that are more rare and exotic, heck the sheer number of possibilities with cold Hardy hybrids alone is staggering and would make for a massive “list”.

 

Worth noting that the page (Jones?) quotes an isolated cold event, not the zone where the palm is planted.

[Dwarf Fan]

27 minutes ago, SeanK said:

Worth noting that the page (Jones?) quotes an isolated cold event, not the zone where the palm is planted.

Thanks for the insight on the data. 

[Than]

I would like to see a list of palms that can take, say 28F, AND frost. THAT would be very useful indeed. So different from 30F without frost I believe. Does any such list exist?

[Las Palmas Norte]

10 minutes ago, ego said:

...Does any such list exist?

Probably not but an overhead canopy does.

[Foxpalms]

On there it shows Chamaedorea elegans as a zone 10 plant however I would say it is a 9b plant that can handle warm 9a winters every few years. As there are people in the UK at 53n that have had them survive 24.8f/-4c. 

Edited December 11, 2023 by Foxpalms