When nurseries discuss cold hardiness of citrus it is important to understand they don’t mean sustained temperatures. They are referring to brief dips to those temperatures of less than 36 hours. Please refer to this article Satsuma - Worth All the Effort
“Satsuma - Worth All the Effort
Satsuma - Worth Every Effort
The Satsuma “orange” (actually a type of mandarin) is generally considered to be the hardiest commercial citrus, and it generally lives up to its name. It has a reputation of being reliably cold-hardy to at least 15F, and perhaps a little lower, as long as the freeze is of relatively short duration. By short duration, I mean less than 36 hours of continuous temperatures below freezing. During freezes of longer duration, Satsuma appears to be only as hardy as other mainstream citrus, and temperatures of 10F or below OR freezes lasting longer than 48 hours will kill an unprotected Satsuma.
Having said that, it’s only fair for me to admit that I live at the absolute northern limit of possible culture for Satsuma. My 20-year average winter minimum is about 15F, meaning that on average, I am pushing it. In February 2003, January 2014, and December 2022, temperatures in my area were around 10F and freeze duration was 48 hours or more, meaning that any Satsuma I plant is probably on borrowed time as an in-ground, unprotected citrus tree.
But I grow Satsumas anyway.
Why? Because Satsumas are THAT good. Because they have good short-duration freeze endurance, they will come through my average winter (whatever that is) without any problems. And they are worth the effort. Fruit quality is excellent, and the fruit here ripen to a beautiful bright orange inside and out. Fruit ripen in fall and are harvested well before my area generally experiences a hard freeze. They also store well under refrigeration for at least a month. Trees stay relatively small, making them easy to protect as needed.
However, last winter was a lesson for me. I had just planted several different types of Satsumas (Ueno, China S-2, Miho, Arctic Frost) the previous summer, and I lost everything except one Arctic Frost and an Owari I had grafted myself some years before and just decided to plant out that year. I even lost a seven-year-old Silverhill (see photo) that had done very well in previous winters. Honestly, I underestimated the severity of the freeze and didn’t think I would actually lose the large Silverhill, but by February I could see that the main trunk was infested by ambrosia beetles attracted to the ethylene gas the dying tree was emitting.
So now I am left to start over, for the most part. I plan to do the following:
1. Limit the number of Satsumas I will plant. It’s too difficult to try to protect everything, so I will limit myself to my favorites. I still have Owari and Arctic Frost, so for the time being I will focus on these.
2. Protect at any temperature below 15F or duration of more than one full day. In retrospect, I wish I had severely cut back my Silverhill and taken radical steps to protect the main stems. Had I done that, I would have lost any chance at fruit this year, but the main tree would have survived and likely made a full recovery. As it happened, I lost the whole thing.”
The last article is good and when they say protect I’m sure you understand they mean Christmas lights etc.
Have you grown Yuzu? 