In my experience Y. elata (the hardiest forms) will be the most hardy trunking Yucca. Y. thompsoniana has never survived more than 2 winters in my garden (z.4b/5a). Of course, my winters can hit -30C, so maybe you'll have better luck... Oh, and select Yucca gloriosa have done much better than thompsoniana for me.

My guess would be that Y.Faxoniana(rz5) would be in there too,right?

http://coldhardycactus.com/Pages/YU005.htm

Y.Torreyi rz5

I think everyone here is right, but I think it has alot to do with how you plant it and where. Never give up, if one dies it does not mean that another one will. For me joshua trees are very hardy, as you can tell from my pics they are the only ones I have with trunks, but I dought they would hardy at all in the midwest.
Soap tree yuccas are very hardy, but when they are young they like to freeze back as do most tree yuccas, but they do very well when older. Plant yuccas high and keep the crowns dry in the winter and you will have much better luck. 😀 There is some simi-dwarf trucking yuccas that will do good for you! Y. gluaca (some forms), Y.baccata? Yucca utahensis etc...

Yuca glauca does the best around my palce, even better than filamentosa. The filamentosa will have occasional leaf damage, while glauca seems bullet-proof.

Welcome aboard, McKatelyn, looking forward to seeing your yucca photos.

Barb

Thank you Barb, I still need to figure this whole posting pics thing out.lol I'm going to take a 2 day trip to Saugatuck MI next week. It's a mini trip because it's only a couple hrs away. It's a very warm zone 6b (I suspect really a 7a). Anyway, there is a unusually huge filamentosa thats foliage has to be more than 4 feet tall growing by the entrance to the city. I want to snap a couple shots of that yucca just to show how giant this specimen is. Btw, the book I was talking about does list faxoniana as hardy to zone 5. I have also heard the smaller leafed Joshual tree is extremely cold hardy but not in our climate with an average of 37 inches of rain per year.

McKatelyn, I would buy smaller one gallon yuccas and try them through the winter. The bigger ones you have in the pots may not be worth the money too experiment with but in time the larger yuccas in the pots may stop growing/ or look weak in time (from what I seen).
I would forget about exact zone claims, I have seem thompsoniana freeze way before rostrata, but I think in many ways it depends on the plants as individuals. Some will just do better than even the same plants from the same batch of seeds.

PS I have not seen Yucca Faxon hardy in my garden without cover in winter, but they can vary greatly, so I keep trying. Maybe as mine gets bigger it will do better. 😉

Also welcome aboard. 😀

I don't disagree with anyone. Welcome to palms north. My thompsonianas do way better than my rostratas in the winter. I am in zone 7a however.
How and where they are planted and the vigour of each plant plays a huge role. Dry and well drained in the winter with southern exposure sure can help.
My trunkers here have been in the ground three years or less.. they are trunking glauca, gloriosa variegata, & baccata. Many other of mine will trunk, just not yet.
I surely want to suggest Yucca elata 'Utahensis' as the possible hardiest trunker, besides trunking glauca. My utahensis yuccas are still babies, but may get one planted before fall. They are supposed to be good to zone 5a? davesgarden.com says good to 4a. Believe it when I see it.

Trunking yucca glauca:

<a href=" http://www.flickr.com/photos/seedscanada/7348602600/" title="Lincoln-20120607-00816 by seedscanada, on Flickr"><img src=" " width="480" height="640" alt="Lincoln-20120607-00816"></a>

<a href=" http://www.flickr.com/photos/seedscanada/7161355741/" title="IMG-20120404-00597 by seedscanada, on Flickr"><img src=" " width="480" height="640" alt="IMG-20120404-00597"></a>

cheers!

Thanks everyone for the warm welcome 😀 When I planted my elata between 8 and 10 years ago, it was a 5 gal size. It has survived just fine (although it's not to vigorous probably due to much shade). That one was from a Arizona nursery that I don't think is in business anymore. Last year I planted a 1 gal size that I picked up cheap at a roadside nursery in Palm Springs. I also planted it one south side of house under house overhang for rain protection. It actually gets more sun than my old one and we had a really warm winter. Guess what, it didn't make it. It does make sence that the Utah ones would be much hardier since that has to be the northern limit for them. Do you know how tall that form gets at maturity or where they sell larger size ones? Thanks again

🙂

You might want too look for plants from New Mexico and West Texas nuresries, places where the plants may come from seed that have seen more cold. 🙂

Aaron is giving you some good advice there-but when it comes to what size plant to
buy,that is a tough one because the larger ones should be tougher than smaller ones
so you may have a better shot with a bigger plant but at great $$ risk.

Unfortunately I think Joshua trees don't like the mid-west/east to much
to much rain and humidity-well.....normally.

McKatelyn, any pics of your garden? 😀

I will take some pics when I get some time. This is such an awesome forum 😮

This is such an awesome forum 😮

That's why I'm spending a lot of time reading and enjoying! It has been making united many people through over North America, Europe and even Asia 😳