Archontophoenix cunninghamiana and -8°C

[Tomas]

Recently I have learned that a person living near the Nightcap National Park in Australia, close to the New South Walles-Queensland border, has experienced in her garden temperatures of -8°C for two consecutive nights. This hard freeze has killed and damaged many plants, but her few Archontophoenix cunninghamiana were undamaged. Now that temperature is much lower than any survival one I have ever seen mentioned and the palm is also naturaly occuring in the Park. I would like to know what you think about.

Tomas

[osideterry]

17-18F just doesn't seem possible when mine were 50% defoliated at 25F (-3C to -4C)

[Jonathan]

Hi Tomas,

You need to be aware that the geography of North East New South Wales is very diverse, with rolling hills, sheltered valleys, mountains and high tablelands. You could be inland from Night Cap on the low lying river plains (say within 50km at Casino), and get some radiational frost in winter, but the terrain of the park itself is mostly hilly and covered in thick rainforest. These areas where the Bangalow palms live are generally sheltered and mild and would basically never see frost.....the odd cold night, but the days are always warm, even in winter - here is a link to show you what the climate is like at Casino: Casino Climate - every month has an average high temperature of over 21C!

Here is a link to a Palmtalk thread on this topic from last year.

Hope this helps.

Cheers,

Jonathan

[epicure3]

Maybe they aren't Archontophoenix? Otherwise, I would be suspect.

[Logolight]

The "Illawarra" is a variation of the A. Cunninghamiana and is believed to be the more cold hardy of the species. These may be examples of the "Illawarra".

[Bennz]

I know of several cases of bangalow palms surviving -8C. It does happen. The subtropical coastal NSW/QLD area got some nasty cold a couple winters back, and -8C was recorded in several sites,... presumably this was the time in question. It happened also in the early 1990's, I was in the are a few months later and saw the damage. A property about 1km away from my inlaws house lost all their palms. Some bangalows survived in the area, and by the time I saw them, had fully recovered.

I think the most important thing to remember is that cold of this type in subtropical Australia would be of very short duration, and total hours below 0C would not be great.

My brother/sister-in-law live about 150kms away from Brisbane in a small NSW town that gets down to -5C every winter, and -8C on occaison. When I see icicles still hanging from the second storey balcony at 10.00am I know it is cold! My bro-in-law tells me the garden water pipes burst some years. But the native populations of bangalow palm survive this kind of temperature.

This area is most certainly not Illawarra, Illawarra is a much milder-winter coastal area (usually totally frost-free) 1000kms further south in a much more benign climate zone. Most of the Illawarra region would have mean minimumn coldest month temps about 5C warmer than the inland subtropical zones, and extreme low temp 5-8C warmer. The slighly lower mean annual air temperature of the Illawarra region does not mean increased frost resistance.

[Tomas]

I am sorry about posting this parallel topic, I have even read the topic Jonathan is linking to, but forget about it, well that's my poor memory.

So just another piece of the puzzle, the person is an experienced plant grower so I believe if she says it was -8°C her measuring is true, maybe just a bit different around the plants, but the bangalows are reported undamaged.

So strange these palms are so widely grown even in marginal climates, but nobody has ever tried the seeds from the places with so extremly low temperatures.

Tomas

[Alberto]

Ciao Tomas!

I´m growing 12 seedlings of bangalows that came from Urbenville... I hope they will show more cold hardiness than the regular ones!

BTW Are you Tomas Kubicek?

[Tomas]

Olá Alberto,

yes, that's me, how are you? I am very curious to know how your seedling will do this winter, you seem to be the only one having those seeds out of Australia.

Tomas

[Cikas]

-8°C

[Shirleypalmpaws]

-8°C !

[Dr Bob Williams]

Tracy,  California

Though we live in a area not usually considered a great palm growing area (other then the the desert loving palms)  I have grown,  in the ground over 30 difference species of palms.  So I have experimented with a large variety of  palms and found with a little extra care when they are young, they all do extremely well. 

Climate here  is a KG #9b with Hot summers and temps up to 108 d f (42 c)  at times with no rain for 9 months and 3 month of cold foggy winters. In the winter  temperatures will usually dip below 0 degrees a couple month thogh rarely below 28 d f ( -3 c. )  . However we have had very rare years were the temp has been as low at 25 f ( -5 c). or about 5 d c.  Basically a desert climate with a nighttime ocean breeze.

I have raised over 30 different species of palms and with a little extra care particularly when they are small and young despite the belief that this is not a palm growing area.  Though some very tropical palms will not even tolerate temps below 50 d f ( 10c d) many if not the majority can thrive if you can protect them from the killer frost. 

Concerning the Archontophoenix cold hardiness.  (King palms) .

What I have found out in general is that with cold hardiness size does matter and the health of the tree going into the winter makes the biggest difference in survival.  .  The bigger they are and the healthier they are the more cold hardy they become which make sense.  Also and as important is the the the growth rate at the time of the frost.  If the temperate go down slowly the palms also decrease growth and some even go into a semi dormancy.  The more dormant they are when the frost hits the better they do.    

I have two different Archontophoenix  raised  from seedling now about 25 years old.

One is a  Alexandrea which is 25 years old and over 40 feet tall. It has thrived despite many winters below freezing.  However when it was young I protected it with covering and heat lights.

The other one was a Cunninghamiana which I believe was labeled as a seeding as a Illawarra variety.  Now supposedly the most cold tolerant of all the King palm varieties it did suffer as a seeding and we almost lost it 15 years ago when we had a record cold to -5 c for a week despite a covering and heat lights.  Now at the time it was very thin and only maybe 10 feet tall.   It made it through and now is about 20 tall (basically about half the size both in trunk diameter and total height to the Alexandrea).  However it still has a narrowing in its trunk as result of this severe winter reminding us of the severe winter when we though we lost it.  Interesting the Alexandrea has no physical signs of any damage.  

Though planted as seedling at the same time  the Cunninghamiana was exposed all day to direct sun light (In the middle, of the central California Valley  we may not see a single cloud for 6 months ) where as the Alexandrea is blocked by direct sun about half the day by  shade from other trees and house.   This I believe is the primarily reason  the Alexandrea thrives where the Cunninghamiana continues to struggle.   

Also there is no evidence of sun burn to the Alexandrea were as  the Cunninghamiana certainly has evidence of  burn both in the trunk and leaves but continue to grow otherwise.  Also Cunninghamiana basically seems to completely stops growing in the winter (semi dormant ) were as the Alexandrea will continue to grow in the winter though much slower then in the summer. 

So my success in growing certain palms that are cold sensitive where they are not suppose to grow is:

1) Protect them against frost when they are small.  The larger they are the more frost resistant they become. 

2) Do not fertilize or induce growth in the cold months. Keep them watered (depending on the type) but do not promote growth in the cold months. The more dormant they are the better they will tolerate the frost.   

3) Protect those palms which do not like sun from the sun as possible. It will stress damage them and make them more susceptible to frost damage in the winter.    Alexandra palms like partial sun but will burn in direct sun all day ( they do not like the desert if not protected).   Where as desert palms like the Washingtonian filifera and the dactlyliferia's require direct sun as much as possible.

R Williams MD 

 

 

 

 

 

[Xerarch]

2 hours ago, Dr Bob Williams said:

Tracy,  California

Though we live in a area not usually considered a great palm growing area (other then the the desert loving palms)  I have grown,  in the ground over 30 difference species of palms.  So I have experimented with a large variety of  palms and found with a little extra care when they are young, they all do extremely well. 

Climate here  is a KG #9b with Hot summers and temps up to 108 d f (42 c)  at times with no rain for 9 months and 3 month of cold foggy winters. In the winter  temperatures will usually dip below 0 degrees a couple month thogh rarely below 28 d f ( -3 c. )  . However we have had very rare years were the temp has been as low at 25 f ( -5 c). or about 5 d c.  Basically a desert climate with a nighttime ocean breeze.

I have raised over 30 different species of palms and with a little extra care particularly when they are small and young despite the belief that this is not a palm growing area.  Though some very tropical palms will not even tolerate temps below 50 d f ( 10c d) many if not the majority can thrive if you can protect them from the killer frost. 

Concerning the Archontophoenix cold hardiness.  (King palms) .

What I have found out in general is that with cold hardiness size does matter and the health of the tree going into the winter makes the biggest difference in survival.  .  The bigger they are and the healthier they are the more cold hardy they become which make sense.  Also and as important is the the the growth rate at the time of the frost.  If the temperate go down slowly the palms also decrease growth and some even go into a semi dormancy.  The more dormant they are when the frost hits the better they do.    

I have two different Archontophoenix  raised  from seedling now about 25 years old.

One is a  Alexandrea which is 25 years old and over 40 feet tall. It has thrived despite many winters below freezing.  However when it was young I protected it with covering and heat lights.

The other one was a Cunninghamiana which I believe was labeled as a seeding as a Illawarra variety.  Now supposedly the most cold tolerant of all the King palm varieties it did suffer as a seeding and we almost lost it 15 years ago when we had a record cold to -5 c for a week despite a covering and heat lights.  Now at the time it was very thin and only maybe 10 feet tall.   It made it through and now is about 20 tall (basically about half the size both in trunk diameter and total height to the Alexandrea).  However it still has a narrowing in its trunk as result of this severe winter reminding us of the severe winter when we though we lost it.  Interesting the Alexandrea has no physical signs of any damage.  

Though planted as seedling at the same time  the Cunninghamiana was exposed all day to direct sun light (In the middle, of the central California Valley  we may not see a single cloud for 6 months ) where as the Alexandrea is blocked by direct sun about half the day by  shade from other trees and house.   This I believe is the primarily reason  the Alexandrea thrives where the Cunninghamiana continues to struggle.   

Also there is no evidence of sun burn to the Alexandrea were as  the Cunninghamiana certainly has evidence of  burn both in the trunk and leaves but continue to grow otherwise.  Also Cunninghamiana basically seems to completely stops growing in the winter (semi dormant ) were as the Alexandrea will continue to grow in the winter though much slower then in the summer. 

So my success in growing certain palms that are cold sensitive where they are not suppose to grow is:

1) Protect them against frost when they are small.  The larger they are the more frost resistant they become. 

2) Do not fertilize or induce growth in the cold months. Keep them watered (depending on the type) but do not promote growth in the cold months. The more dormant they are the better they will tolerate the frost.   

3) Protect those palms which do not like sun from the sun as possible. It will stress damage them and make them more susceptible to frost damage in the winter.    Alexandra palms like partial sun but will burn in direct sun all day ( they do not like the desert if not protected).   Where as desert palms like the Washingtonian filifera and the dactlyliferia's require direct sun as much as possible.

R Williams MD 

 

 

 

 

 

Dr Bob Williams, welcome to the forum! Heck of a post for a first timer, but sounds like you've long been growing palms.

[sonoranfans]

Good observations Dr Wiliams.  Im sure the information will help others in similar climates.  Here in florida the alexandre are known to be more sun tolerant than cunninghamiana.   I cannot speak of experiences growing in the inland CA desert though.