Unprotected Plumeria in Ground in Zone 8b/9a? Apparently So

[Matthew92]

Upper Gulf Coast: zone 8b winters: Washingtonia robusta: mostly defoliated, Plumeria: above ground stems survive!??
 

Just recently happened onto an amazing find of Plumeria in ground in my area.

 

[Matthew92]

Could swear the above pictures are somewhere in Hawaii. Just absolutely awesome.

Now for the background. This location is Okaloosa Island, which is well known to be a slight microclimate. In the several years before the 2014 and 2015 winters, queens, Washingtonia, Phoenix canariensis would adequately survive here in this microclimate while just not that further north on the mainland, there was 50% or more canopy damage to such trees. However, in 2014, thanks to the polar vortex, it is under my belief that all the way to the ocean 8b temps occurred. I witnessed Washingtonia robusta and even some filibusta 100% defoliated all the way to the ocean. Phoenix dactylifera and canariensis as well were severely damaged with some even dying. Philodendron selloum and Strelitzia nicolai plants that had grown to considerable stature over the years were turned to mush.

Here is the streetview in summer 2013 the year before the devastating freezes.

[Matthew92]

Now here are pictures in April 2015 after two harsh back to back winters. The 2014-2015 winter as well had temps into the teens on the mainland, and I estimate that the barrier islands couldn't have been any warmer than mid-20's.

This picture is taken right next door to where the plumerias are. As you can see, Washingtonia have stunted, burnt crowns with one looking dead. This area undoubtedly saw serious cold. 

 

[Matthew92]

This appears to be the standard white variety of plumeria. I actually have one in a pot at my place. The lazy bum I am, I've left mine out in temps in the high 20's before. It will lose it's leaves, but come back slowly in the spring. I also have a pink one that seems slightly more tender to cold. It took frost and temps slightly below freezing about the same as the white: there was just one stem that the very top was burnt and in the spring, it started branching profusely at that point.

I've hard a hard time researching what plumeria variety is the most cold hardy and what temp it will take. If I had to guess, I would say it would be hard pressing to find another plumeria variety more cold hardy than this white one.

[Really full garden]

When I lived in Houston ,Tx. it was zone 8B and I had several large plumerias that were planted out in April and pulled up in November. They were stored in the garage bare root .

They always bloomed and looked great during the long hot growing season.

[Ben in Norcal]

How is this possible? I'd love to know the secret??

[Silas_Sancona]

Interesting. Wonder how cold it got and for how long in that area.  Regardless, as a rule, White and yellow-flowering cultivars are among the hardiest/easiest to grow.

Plumeria rubra itself has a pretty sizable distribution starting somewhere in the foothills of Sonora, Mex. roughly to the east of Hermosillo, extending all the way down through Central America. Plants in the Tropical Deciduous Forest region of Sonora almost always have White flowers. Plants from warmer/more tropical parts of Mexico and Central America exhibit colored flowers.  In that respect, id suspect cold tolerance follows a individual cultivar's pedigree ( more color, possible less cold tolerance) especially when other, less cold tolerant species are included in the genetic makeup of a hybrid. ( P obtusa X P. Rubra =  potentially less cold tolerant offspring, especially if P. obtusa traits dominate)

Some of the hardiest plants i have were seed-grown, white flowering and survived a couple nights briefly exposed to frost as year old seedlings with minimal damage. Seed came off a specimen  labeled "San Pedro Du Lac" id picked up in Homestead the first time i visited Florida years ago. Supposedly this cultivar was discovered growing in a higher elevation location in Guatemala by the grower i bought it from.

 

Edited August 29, 2016 by Silas_Sancona

[necturus]

I've started seeing a lot of plumeria in yards here. Most are still relatively small, although I know of two that are as large or larger than the one posted here. I think this stems from how common and cheap they are in some of the big chain nurseries. When you can get a gallon pot with a nice, branched cutting in it for 6 bucks you can practically treat it as an annual.

I suspect the large size of this plant pre-freeze probably provided some frost/cold protection that allowed the inner branches to survive. 

Nice plant! I definitely intend to plant one in the future.

[Matthew92]

Turns out that the white plumeria I have was given to us by the person who lives in that house!

[Bennz]

Hi Opal92, I missed this first time around, impressive! How much moisture in the ground was there in the big freeze? I'm guessing that the soil is super free draining, and the heat of the warm summer is enough to compensate for a short period of cold. Sound about right?

This post is another example of how useless USDA zones are outside continental USA! Plumeria grow fine outside under rain cover in my cold but borderline USDA 10/11 garden, but put them in the ground with wet roots and they rarely survive the winter.

[Matthew92]

On 5/11/2017, 6:49:30, Bennz said:

Hi Opal92, I missed this first time around, impressive! How much moisture in the ground was there in the big freeze? I'm guessing that the soil is super free draining, and the heat of the warm summer is enough to compensate for a short period of cold. Sound about right?

This post is another example of how useless USDA zones are outside continental USA! Plumeria grow fine outside under rain cover in my cold but borderline USDA 10/11 garden, but put them in the ground with wet roots and they rarely survive the winter.

Yes, the soil is extremely fast draining beach sand there.

Just came back to this thread after awhile. Since my last comment, my dad drove by this house (the person who lives there was a co-worker of his) during a cold snap and found that the large plant to the right of the driveway was being protected with a huge tent! However, I'm not sure about the smaller ones in the yard if they were protected or not. Still, an impressive feat.