This past winter myself and other PNW citrus enthusiasts successfully over wintered our Meyer lemons (among other varieties) outdoors and in the ground with little fuss and some protection. I had mine covered and heated with Christmas lights on about 21 nights and 10 days this past winter. We had a low that bottomed out at around 10f or -12c for a couple of hours - others did not get that cold. I did not loose any leaves or the immature fruit that was on the tree. My bushes are only about 2' tall at this point and on a unknown rootstock. Recently, I got a Harvey Lemon which is a true lemon?? and its apparently the hardiest of the lemons. What sort of temperatures will a Harvey survive - assuming that it is fully dormant and a mature tree. I know there are many variables here, like age of tree, chosen rootstock, duration of low temperature, dormancy, soil conditions and humidity etc.

Can anyone provide which lemon cultivar is hardier Meyer or the Harvey?
Is there a hardier lemon strain? - Something that looks and tastes like a grocery store lemon.

Thanks, Greg

Greg I have both Meyer & Harvey in the ground. Both are on their own roots. The Meyer is hardier than the Harvey for sure. The Harvey gets leaf & branch die back where the Meyer has yet to have any damage at all. This past winter we had a low of 24 F & the Harvey had quite a bit of damage. The Meyer once again had no damage at all.

Grafting the Harvey to Trifoliata may impart more cold tolerance but I doubt more than a few degrees.

Thanks Laaz. Thats a good benchmark for me.
Are you aware of any other cold tolerant lemons? I saw that our friends in CA had some problems with the Eureka lemons and the lisbons seemed to pull through this winters cold snap with better success.

I have a Harvey Lemon, and it is a great tree. Harvey Lemon is hardier than Eureka and Lisbon, but not by much. When the word HARDY is used to describe various citrus cutivars, it is a real stretch when applied to Harvey Lemons. - Millet

Hi Millet, I have a stupid question.
If you grow all your citrus in a controlled greenhouse, at same temps, how can you tell which is hardier than the other?

a) you forgot to turn on the heater during the turn of the season
b) the heater broke down during the cold season and have evaluated the survivors first hand
c) you intentionally did not turn on the heater to test which one is hardy
d) if potted, you bring them outside and forgot to bring them in before the first frosts came.
e) if potted, you bring them outside and intentionally not bring them for testing which one is hardy.
f) none of the above, just learn about them from credible people or from credible books.

Good answer to a "stupid question" LOL

My inground Meyer Lemon has also over-wintered successfully. I'm in the same PNW region as Gregn. Looking forward to another growing season, though this time my tree will have been acclimatized and will have fruit development later in the year.

Gregn, I replied to your note on the UBC Citrus Forum. Please have a look. I've asked you a couple of questions re: expected fruit yield this year.