Washingtonia robusta in zone 8

[Denis.green.garden]

Do you think washingtonia robustas could grow in zone 8 or would i need to protect them and can i leave them unprotected once established? 

[Leelanau Palms]

Sounds like one for @WSimpson 😀

[knikfar]

So much of that depends on what kind of zone 8 you're in. Here in North Carolina, most of the state is now in zone 8. But outside of coastal areas, any washy is going to need protection during the winter. The coast is still zone 8 but it's 8b. Even there, the only washies that I see survive long term are at the southern end of our coast in the Wilmington area. In that area, washies don't normally need any protection but might need some during an extreme winter. 

[MarcusH]

Robusta will do well in 9a and up .  A Robusta will struggle to survive in 8a and will defoliate in 8b winters.  It's not a good palm for zone 8 to be honest. If you're in a warm 8b it will do fine . 

[SeanK]

7 hours ago, MarcusH said:

Robusta will do well in 9a and up .  A Robusta will struggle to survive in 8a and will defoliate in 8b winters.  It's not a good palm for zone 8 to be honest. If you're in a warm 8b it will do fine . 

Have to agree on this. The ones I saw in Augusta, GA were never protected but also never saw freezing precipitation. They likely never saw below 15°F and some years stayed above 20°.

[ZPalms]

washies are great zone pushers, you'd need to protect it most likely, I'm 8a but have 6 washies in the ground and its almost been a full year since I transplanted them and they look great

[Yeehova]

I am in coastal NC.  My young washingtonia made it through 2 winters unprotected, but the fronds typically brown in the dead of winter.  Fast growing though.

[Marco67]

On 5/21/2024 at 9:15 AM, Denis.green.garden said:

Do you think washingtonia robustas could grow in zone 8 or would i need to protect them and can i leave them unprotected once established? 

Unfortunately, you have a damp/cool zone 8. I don't think Washingtonia's will make it in Germany unprotected for very long and will need protection most winters. Filifera's are a bit tougher but are nearly impossible to get. Most Washingtonia's you buy are Robusta or Filibusta's. 

[NBTX11]

Must be a very warm 8b. Robusta grew for decades in hot Texas 8b climates to reach very impressive heights. I would say it needs to be in an 8b climate that is close to 9a and has lots of 9a characteristic. 

[WSimpson]

On 5/21/2024 at 3:15 AM, Denis.green.garden said:

Do you think washingtonia robustas could grow in zone 8 or would i need to protect them and can i leave them unprotected once established? 

A Filibusta would be hardier . There's one that Knikfar has been selling ( or giving them away ? ) from Fayetteville , North Carolina that has been growing outside without protection for  a lot of years and has seen some  temperatures under 10F . 

The problem in my climate is that I can have one cold snap that makes my winter a 7A winter ( 5F-9F )  , then  the next coldest temperature that winter might only be 15F-20F . 

So if you get continental cold snaps every now and then you might want to see how your winters compare to Fayetteville winters . Fayetteville is also one of the hottest parts of North Carolina , averaging Highs in the  low 90'sF in the summer and Lows in the summer of 70'sF . So a palm can recover pretty fast in Fayetteville . I'm not sure about your summer heat there . 

Good luck and keep us posted on your decision .

Will

 I just checked the Fayetteville averages and the average  Highs in the coldest part of  January are    52.4F and the average  Lows that time of year  are  32.8F .

The hottest parts of summer in July average 91.4F and the average Low that time of year is 71.8F . All that means less  if a severe cold snap comes down from Canada , but hot summers help recovery .

 

Below is my heavily Robusta Filibusta . I protect it when I see a winter temp below 15F .So I protect it about  50% of the winters . It loses all its frond every winter . I do have the heat for it to fully recover with 25-30 fronds a season .

 

[Denis.green.garden]

12 hours ago, Marco67 said:

Filifera's are a bit tougher but are nearly impossible to get. Most Washingtonia's you buy are Robusta or Filibusta

actually where i live i have only seen wash. Filiferas being sold 

[Denis.green.garden]

12 hours ago, WSimpson said:

A Filibusta would be hardier . There's one that Knikfar has been selling ( or giving them away ? ) from Fayetteville , North Carolina that has been growing outside without protection for  a lot of years and has seen some  temperatures under 10F . 

The problem in my climate is that I can have one cold snap that makes my winter a 7A winter ( 5F-9F )  , then  the next coldest temperature that winter might only be 15F-20F . 

So if you get continental cold snaps every now and then you might want to see how your winters compare to Fayetteville winters . Fayetteville is also one of the hottest parts of North Carolina , averaging Highs in the  low 90'sF in the summer and Lows in the summer of 70'sF . So a palm can recover pretty fast in Fayetteville . I'm not sure about your summer heat there . 

Good luck and keep us posted on your decision .

Will

 I just checked the Fayetteville averages and the average  Highs in the coldest part of  January are    52.4F and the average  Lows that time of year  are  32.8F .

The hottest parts of summer in July average 91.4F and the average Low that time of year is 71.8F . All that means less  if a severe cold snap comes down from Canada , but hot summers help recovery .

 

Below is my heavily Robusta Filibusta . I protect it when I see a winter temp below 15F .So I protect it about  50% of the winters . It loses all its frond every winter . I do have the heat for it to fully recover with 25-30 fronds a season .

 

Our summers fluctuate in temperatures. For example the last 2 or 3 summers were pretty hot and dry but this one is supposed to be a bit more temperate and also a bit wetter. Last winter we also had a cold snap down to i think about 10°f which i have never witnessed before.
I think i’ll plant one in a large pot and move it indoors during winter. 
However i am pretty limited on space indoors and was wondering if i could place them in the basement which doesn’t receive a lot of light and kind of try to induce a forced dormancy.
Do you think that would be possible?

[SM458]

I think Germany might be too cold during winter. I live in California where my zone is 8A. I see Robustas, Filifera, and hybrids. My climate is dry and hot in the summers. Cold and wet winter storms during winter. 

[Marco67]

10 hours ago, Denis.green.garden said:

actually where i live i have only seen wash. Filiferas being sold 

Then you are a lucky man. Unfortunately, here in the Netherlands it's 99% Robusta/Filibusta. You can only get pure Filifera's in more specialized garden centers or grow them from seeds. I think both will struggle in Germany without protection though. 

[Than]

Washingtonias are all over the place in zone 9 here but I have never seen one in zone 8. I grew up in zone 8 and never saw one in the entire province. In zone 9 they are weeds.

[Las Palmas Norte]

On 5/21/2024 at 11:37 AM, MarcusH said:

...If you're in a warm 8b it will do fine . 

Unless it's in parts of the PNW with plenty of cold winter rain and periodic freezing.

[ahosey01]

12 hours ago, SM458 said:

I think Germany might be too cold during winter. I live in California where my zone is 8A. I see Robustas, Filifera, and hybrids. My climate is dry and hot in the summers. Cold and wet winter storms during winter. 

I think this is the key.  You could probably grow a filifera - especially if you it big - in a hot 7b like Alamogordo.  If it's wet or mild, though, I think you got no chacce.

[MarcusH]

4 hours ago, ahosey01 said:

I think this is the key.  You could probably grow a filifera - especially if you it big - in a hot 7b like Alamogordo.  If it's wet or mild, though, I think you got no chacce.

Born and raised in Germany here.  There's some people on here who grow palm trees in Germany but let's be honest overall the climate is too cold to successfully grow palms unprotected.  Lack of heat and short summers are against growing palms.  There might be some microclimates near the Rhine River area where chances of survival are higher but overall it doesn't look good in "most" parts. 

[Slifer00]

A very important thing nobody has mentioned is its tolerance to wet freezes. Mature trunks can tolerate a dry -5C with almost no problem,  but a wet -5C will kill them.

[SeanK]

3 hours ago, Slifer00 said:

A very important thing nobody has mentioned is its tolerance to wet freezes. Mature trunks can tolerate a dry -5C with almost no problem,  but a wet -5C will kill them.

What are we talking about here?

W.filifera likely could not be planted small in wet winter areas. Robustas can be planted from 10" pots.

[Slifer00]

4 hours ago, SeanK said:

What are we talking about here?

W.filifera likely could not be planted small in wet winter areas. Robustas can be planted from 10" pots.

For example, cold mixed in with high humidity and/or snow is much more likely to damage washingtonias when exposed to the same temperature. I heard filifera is more cold tolerant, though.

[karlbonner82]

If you live in a cool, "oceanic" zone 8 then forget it.  Here in the PNW there have been probably hundreds of attempts to grow W. robusta, and I've seen at least a dozen of them in person. None that I know of, have survived long enough to get more than 3-4' of trunk.  Not even in the urban centers, which are on the cusp of zone 9.  (There was one developer in NW Portland, years ago, that foolishly planted a bunch of 20' Washys in front of a hotel. Within 5 years they had all died and were replaced with Trachys.)

Washingtonia palms can survive a zone 8 freeze if it's short-lived and the plant is healthy and mature. Unfortunately, neither are the case in most cool zone 8 climates.  The long cool/rainy seasons leave the palms stunted and weak.  I guess you could say they suffer from "seasonal depression" similar to many humans living in cool, gray places. 

[Michael36]

We are in 8b/9a, London Uk. There are several around London that are large. Mine has been in the ground, in a sunny spot, and has pulled thru some bad winters with minimal damage. Snow and -5 winter before last. It has some brown leaf tips but otherwise growing. So, perhaps with a bit of protection. As always, depends on overall conditions. I have a smaller one to my neighbours, they planted in a shady spot and died first winter. 

[Denis.green.garden]

On 5/28/2024 at 8:55 AM, karlbonner82 said:

If you live in a cool, "oceanic" zone 8 then forget it.  Here in the PNW there have been probably hundreds of attempts to grow W. robusta, and I've seen at least a dozen of them in person. None that I know of, have survived long enough to get more than 3-4' of trunk.  Not even in the urban centers, which are on the cusp of zone 9.  (There was one developer in NW Portland, years ago, that foolishly planted a bunch of 20' Washys in front of a hotel. Within 5 years they had all died and were replaced with Trachys.)

Washingtonia palms can survive a zone 8 freeze if it's short-lived and the plant is healthy and mature. Unfortunately, neither are the case in most cool zone 8 climates.  The long cool/rainy seasons leave the palms stunted and weak.  I guess you could say they suffer from "seasonal depression" similar to many humans living in cool, gray places. 

Thanks! This was actually really helpful 

[HiltonHead2004]

Hi! I would say it's possible to grow a W. Robusta in a Zone 8 climate, especially 8B, but it would def take extra effort in protecting it during the winters. If you're up for that, I would say it'll last you several years until the palm gets too large and faces an inevitable freeze. 

[Sabal_Louisiana]

The problem is they grow tall and how do you protect a crown that is 50 feet up in the air?

Here in the interior Deep South, most of the Washingtonias are either hybrid or Mexican (robusta). Though W. filifera likes arid climates, I've seen those grown too with no problem.

The robusta is aptly named because under good conditions they will grow 2-3 feet tall a year.

we have had 4 intense cold waves in the last 6 years. These were the only cold waves of each winter - brief but intense, bring temperatures down to 15-20F. We had some casualties, mainly as a result of the prolonged wetness that followed.  No less than 80% have survived all cold spells including a few that looked collapsed but eventually returned.

The filiferas were much less affected but I have seen one or two succumb to excessive rain and humidity, not cold.

In the 2024 cold wave, it reached 17-18 and almost all have come through and are already looking vigorous.

In the 2015 freeze, the worst, I saw one sprouting green 2 weeks after it hit 15F.

This is in Zone 8b. But before 2018, we were really 9A.

In the humid zones, the risk of mortality will be high below 12F,  moderate 12-15F, low 16-20F and very low above 20F,  if the cold is not prolonged.  Frond burn and discoloration will occur below 22F, the colder it is, the worse it be. Defoliation will occur below 16F.

For Zone 8 I would give the more cold hardy  filifera a shot, on well drained locations.