Cold hardy citrus trees

I love citrus, I eat it pretty much everyday and start my day with orange juice.
A handful of years ago, I found out there were certain varieties I could grow here in zone 7B / 8A

http://en.wikipedia.org/wiki/Cold_Hardy_Citrus


Currently I am growing Owari Satusuma mandarins (very tasty, "zipper skinned") also I have a 3 year old citrangequat tree (not producing yet)
and some kumquats I grew from seed I plan to put out in the yard this year.

My trees are partially protected on the coldest nights, but have seen temps down to 10-15 degrees below freezing with little to no damage.

Some of the most cold hardy varieties are quite sour / bitter / seedy, but I think carefully choosing varieties can allow you to grow citrus where
you would never believe it possible.

You may get away with them for several years, but sooner or later a single-digit freeze will come your way. It eventually did for me while living both near Americus and near Macon, both further south than you by a long way. You need to be able to hastily rig a complete covering with a heat source to keep your trees through such an event. Christmas lights, strung in the tree, are popular for this purpose in CA.

The lowest temp I have seen in recent years is 11F (12C)

I do protect my mandarins more than everything else though, I've protected my Satsuma mandarin trees with row covers and lights until last year when I built
a greenhouse around them.
When temps fall below 30F inside the greenhouse. , a couple of 40watt lights come on in the greenhouse, but 95% of the winter the only heat is passive heating stored from daytime sun.

Everything else is unprotected unless there is a really hard freeze predicted, then I mulch around them and throw a plastic sheet over them.

What were you growing?

Here near Greenwood, SC, I've been growing satsuma (Brown's Select, LA Early, 10 Degree), Hamlin orange, yuzu, citranges, citrumelos. Winter lows typically reach mid to low teens. The yuzu, citranges, and citrumelo are completely cold hardy. For the others I put several water filled gallon milk jugs and t-posts around the base of each tree. Whenever temps are forecast to go below 20F (satsumas), or 27F (orange), I wrap a water heater blanket around the t-post/tree and slip a large plastic trash bag over the top of the blanket. I remove it when warmer temps are forecast for the next 10 days. The bag/blanket will be on and off the tree several times over the course of the winter and will also go over the tree if we have a late frost after the tree has broken dormancy. I choose citrus that mature its fruit before the first fall frosts in Nov and keep the trees pruned to a size that is managable to protect. This spring I'm adding a Bloomsweet grapefruit and a Joey avocado (fruit matures in Sept and is cold hardy to the upper teens F) to the mix.

Something I am doing as an experiment is growing some mandarin trees that I grew from grocery store fruit seeds.
I grew them in pots a couple of years, then put them in the ground a few years ago, last year they completely defoliated, but grew back.
This winter they still have many leaves.
My hope is that I can acclimatize seed grown trees to where I live. If not, I'm not out any money.

This Spring I will have some Kumquats that I grew from seed ready to plant out in the yard.

Cris, This greenhouse you have around your citrus, is it air tight? How big? Did you use corrigated plastic or glass? Gets a little colder than that here but maybe with the lights. I do love kumquats, it would be great to have orange and lemon. Thankyou Richard

My greenhouse is not exactly airtight. It is almost completely constructed of recycled materials-
I have a wood frame with some single pane windows of glass on the sides, the front is sloped to match the winter sun angle
and the front is covered with wood framed plastic windows, the back is solid 3/4" plywood.

I bought some mechanical automatic vents that are normally used for house crawl spaces and put those in the sides. When the temperature warms up
to about 60F they start opening up, and are fully open at 75F or above.

I'm planning on making it bigger this year since I've found more used windows and stuff, but here it is last fall
(just after a large tree branch fell on it)




Here is a picture of it in the summer (windows and back removed)

If Holzer can grow lemons in the mountains of Germany you can grow citrus in zone 7 or 8. You may have to make some tweaks to make it work but it can be done successfully long term. In his new book Sepp has an entire section on protecting frost sensitive plants one of the tips he mentions is protecting cold sensitive plants from morning sun as the rapid warming can cause damage to plant tissues. Also don't forget to mulch deeply.

James Colbert wrote:If Holzer can grow lemons in the mountains of Germany you can grow citrus in zone 7 or 8. You may have to make some tweaks to make it work but it can be done successfully long term. In his new book Sepp has an entire section on protecting frost sensitive plants one of the tips he mentions is protecting cold sensitive plants from morning sun as the rapid warming can cause damage to plant tissues. Also don't forget to mulch deeply.

Yeah, I'd like to see some more specific info on what Sepp does. Only some brief references to some kind of citrus. I've definitely had success growing citrus here in 8A.

There is a difference between hardiness and that the tree is able to ripen the fruit. For example grapefruit grow where I live but taste much like lemons.
You could try Australian native citrus too, they seem to be pretty hardy. Kumquat is the most cold hardy citrus.

Angelika Maier wrote:There is a difference between hardiness and that the tree is able to ripen the fruit. For example grapefruit grow where I live but taste much like lemons.
You could try Australian native citrus too, they seem to be pretty hardy. Kumquat is the most cold hardy citrus.

yes, you are right, That is an important point- the fruit is never as hardy as the tree itself.
Here in the USA I know of many types of citrus that ripens in our Winter period. This is fine in Florida or around the coasts, but further inland there would be a problem with fruit freezing and going bad.
This is one reason I planted Owari (Japanese = Early) Satsuma mandarins, they are typically ripe and ready to eat in November, before we get freezes.

I don't know of any cold hardy Australian citrus. I've heard of finger limes (microcitrus) but I don't think they would do well in below freezing temperatures.

Kumquats are certainly hardy. I have some that I've grown from seed that I will plant out in a year or so. The various crosses between kumquats and other citrus tend to be quite cold hardy also. I have a few citrangequats that are doing very well.

I haven't had any problems with citrus dying from cold yet, however the leaves get a bit yellow over winter. We have a local coop here were people can bring their produce in and I found that local oranges while not very sour simply lacked taste. Local grapefruits were very sour. However the rind is a very important part of the citrus to use and for this you do not need a perfectly ripe fruit.

Funny thing is that the mandarins I have been growing are some of the best citrus I have ever eaten, anywhere.
Full flavor, sweet and juicy.

I have gotten mandarins at the grocery store that were virtually tasteless, insipid flavors.

I think it makes perfect sense from a permaculture standpoint to grow your own citrus, even if it is a small
potted calamondin or dwarf lemon.

I have a question regarding to this particular trees. I have found one site, about different sorts of trees, it has articles about Christmas trees, shrubs, but that isn't what interests me. The part what I wanted to ask is, what are your experiences about citrus trees that are on this site? Are they easy to grow or tricky?

a little off topic but we live even further north in western n.c. and we get below zero quite a bit. there are "feral" citrus trees around here, my father said they were Ponsirus Trifolia (don't know if I spelled that right), they're similar to the filippino "calamunzi", sort of like lemons but smaller. They're quite strong, not really great for straight up eating but make awesome lemonade or additions to meals. I would suspect these critters would be fine for growing just about anywhere in the mid-south.

I don't know their common name, but was quite shocked to find them growing out in the wild. Word of advice though, they have HUGE thorns

Poncirus trifoliata
Hardy down to zone 5! Technically it's considered an orange, although it does look more lemon like and is only distantly related to common citrus fruits. By comparison mandarin oranges are only hardy down to about zone 8.

M Foti wrote:a little off topic but we live even further north in western n.c. and we get below zero quite a bit. there are "feral" citrus trees around here, my father said they were Ponsirus Trifolia (don't know if I spelled that right), they're similar to the filippino "calamunzi", sort of like lemons but smaller. They're quite strong, not really great for straight up eating but make awesome lemonade or additions to meals. I would suspect these critters would be fine for growing just about anywhere in the mid-south.

I don't know their common name, but was quite shocked to find them growing out in the wild. Word of advice though, they have HUGE thorns

Common names I've seen: Bitter orange, Chinese / Japanese bitter orange, Trifoliate orange, target practice orange...

Hey, I work in WNC (Franklin) . Across the border in Georgia where I live there is one large poncirus trifoliata in the middle of town that has fruit every year. I've never seen any in the wild though. I think these are really cool plants. I've started over 20 on my 2 acre property, most of them as a fence.
The thorns are truly horrific, so they great for a natural fence. The trees have a really interesting look year round.
The flavor of the fruit is sour and bitter, with a pine resin aftertaste.

I have a calamondin (calamunzi) tree in a pot, and as sour as those fruit are, they taste 100 times better than PT fruit!

I planted a citrangequat tree in my yard a few years ago, these are a cross between a PT and a sweet orange, (citrange) which was then crossed with a kumquat.
These are supposed to be one of the closest things to a very hardy citrus that can take temps in the teens (F) and make decent useable fruit.

I have three potted trees that I take in and out in Oregon. One is grapefruit, my oldest, over 30. I seldom get fruit, but the flowers are to die for. A friend picked them up from underneath and said, "Save these for tea." I love smelling them though, so I haven't yet used them for tea. The second is a Bearss lime, also a lovely little tree. I get lots of delicious limes from it. The flowers are dainty and hardly have any fragrance. The third is a mandarin. I get some fruit, which I eat whole, skin and all. They are delicious. I would not risk leaving them out in winter, and they tend to bloom when I bring them in. I take them out sometimes when it is sunny, on the enclosed front porch. Being inside gets to be a challenge at the end of the season.

As for Sepp, I believe he uses both water to retain heat and reflect light and rocks for the same purposes.

The grapefruit in bloom is my Christmas tree. I put little balls on it.

Cris Bessette wrote:

M Foti wrote:a little off topic but we live even further north in western n.c. and we get below zero quite a bit. there are "feral" citrus trees around here, my father said they were Ponsirus Trifolia (don't know if I spelled that right), they're similar to the filippino "calamunzi", sort of like lemons but smaller. They're quite strong, not really great for straight up eating but make awesome lemonade or additions to meals. I would suspect these critters would be fine for growing just about anywhere in the mid-south.

I don't know their common name, but was quite shocked to find them growing out in the wild. Word of advice though, they have HUGE thorns

Common names I've seen: Bitter orange, Chinese / Japanese bitter orange, Trifoliate orange, target practice orange...

Hey, I work in WNC (Franklin) . Across the border in Georgia where I live there is one large poncirus trifoliata in the middle of town that has fruit every year. I've never seen any in the wild though. I think these are really cool plants. I've started over 20 on my 2 acre property, most of them as a fence.
The thorns are truly horrific, so they great for a natural fence. The trees have a really interesting look year round.
The flavor of the fruit is sour and bitter, with a pine resin aftertaste.

I have a calamondin (calamunzi) tree in a pot, and as sour as those fruit are, they taste 100 times better than PT fruit!

I planted a citrangequat tree in my yard a few years ago, these are a cross between a PT and a sweet orange, (citrange) which was then crossed with a kumquat.
These are supposed to be one of the closest things to a very hardy citrus that can take temps in the teens (F) and make decent useable fruit.

franklin is about half an hour east of us not far at all. My g/f is filippina and her late mother used to grow calamunzi. She mainly grew them as a joke I think, but we hit it off right away when I liked them and ate them like fruit haha. The trifoliate that is growing over here "wild" has fruit that are actually quite good, the skin does have that piney smell to it, but the fruit doesn't seem to possess it. I've not detected any bitter notes either, but we all know we can get variance depending on many factors. I've tried starting some from seed off of this tree, but not been very lucky yet, I may try to root a cutting this spring. I think it would be nifty to have around. We do have some Calamunzi growing in our home, but they do not get adequate light to flower or fruit. The calamunzi did quite well in eastern n.c. growing inside a little sunroom attached to the in-law's house.

I know they aren't technically in the same family as typical citrus, but I wonder if anyone has tried to cultivate a cross between Trifoliate orange and a more tame citrus to make something that is cold hardy and able to be eaten out of hand. It isn't impossible to create a hybrid across such gaps. As I recall the Shipova is one such fruit that was a cross between two genera. It could be a worthwhile project if you could keep the less hardy plants alive long enough to make the attempt.

M Foti wrote:
........
franklin is about half an hour east of us not far at all. My g/f is filippina and her late mother used to grow calamunzi. She mainly grew them as a joke I think, but we hit it off right away when I liked them and ate them like fruit haha. The trifoliate that is growing over here "wild" has fruit that are actually quite good, the skin does have that piney smell to it, but the fruit doesn't seem to possess it. I've not detected any bitter notes either, but we all know we can get variance depending on many factors. I've tried starting some from seed off of this tree, but not been very lucky yet, I may try to root a cutting this spring. I think it would be nifty to have around. We do have some Calamunzi growing in our home, but they do not get adequate light to flower or fruit. The calamunzi did quite well in eastern n.c. growing inside a little sunroom attached to the in-law's house.

I'm surprised you are having problems growing these from seed. I find them very easy to start from seed.
The fruits are generally packed with seeds, so plenty of chances!

In the past I've taken some of the fallen fruit around the tree near here and I cut it open, dump the seeds in a pot with some potting soil.
I put them under a florescent lamp on a shelf and within a week and a half on average they are starting to sprout.

citrus seeds in general like warm soil to germinate in.

D. Logan wrote:I know they aren't technically in the same family as typical citrus, but I wonder if anyone has tried to cultivate a cross between Trifoliate orange and a more tame citrus to make something that is cold hardy and able to be eaten out of hand. It isn't impossible to create a hybrid across such gaps. As I recall the Shipova is one such fruit that was a cross between two genera. It could be a worthwhile project if you could keep the less hardy plants alive long enough to make the attempt.

Yes, they've been working on that since the late 1800's :

http://users.kymp.net/citruspages/trifoliates.html (Edit: This site died, here is the new location: http://citruspages.free.fr/home.html
)

The citrange is the cross between the trifoliate orange and a sweet orange. I have some citrangequat trees, which are a cross of the citrange with a kumquat, (tri-generic)

Oh yeah, the poncirus trifoliata is also known as citrus trifoliata.

I started last year with planting some trifoliate oranges from local seeds. Several of the better seedlings look to be coming through the winter in very good shape so I'm hopeful of getting them big enough to transplant out with critter protection before next winter.

I am very interested in several of the cold-hardy crosses. I want to establish trees from the varieties that can survive in this zone, in hopes that even the ones that won't normally make fruit might do so in an unusual year. Global climate change is a wild card but I'm trying to make it work for me!

Chris Bessette's link from 2013 has gone to the great 404 in the sky. So I went and found an Internet Archive version of the link:

https://web.archive.org/web/20141007155939/http://users.kymp.net/citruspages/trifoliates.html

Dan Boone wrote:Chris Bessette's link from 2013 has gone to the great 404 in the sky. So I went and found an Internet Archive version of the link:

https://web.archive.org/web/20141007155939/http://users.kymp.net/citruspages/trifoliates.html

Thanks, I'm guessing the owner had to change internet providers, I found the NEW site that is updated here:

http://citruspages.free.fr/home.html

Dan Boone wrote:I started last year with planting some trifoliate oranges from local seeds. Several of the better seedlings look to be coming through the winter in very good shape so I'm hopeful of getting them big enough to transplant out with critter protection before next winter.

I am very interested in several of the cold-hardy crosses. I want to establish trees from the varieties that can survive in this zone, in hopes that even the ones that won't normally make fruit might do so in an unusual year. Global climate change is a wild card but I'm trying to make it work for me!

I'm also in zone 7A and I'm trying the same thing. So far the trifoliate orange (poncirus) is obviously perfectly suited for this environment, but, unfortunately, the fruit need a bit of processing to be useful for anything more than target practice. I have over twenty planted around my property- only one mature enough to produce fruit so far.

The other cold hardy varieties I have that I have hopes for are standard Kumquat and Citrangequat. I have 2 Kumquats in the ground that are surviving pretty well. My citrangequat got pretty burnt last Winter,
but came back.

My favorites though are my Owari Satsuma mandarin trees. I have two of these planted in the ground in my greenhouse, these have survived without damage for 4+ years now, and have possibly the best eating citrus
fruit of any that I know, including "regular" citrus.

Doh! I never thought to look for an updated link. Thanks for posting it.

I think kumquat is going to be the next thing I try. I don't have a decent greenhouse situation or any great way to protect trees very much, so I'm going to focus on stuff that "ought" to survive the local conditions.

Dan Boone wrote: Doh! I never thought to look for an updated link. Thanks for posting it.

I think kumquat is going to be the next thing I try. I don't have a decent greenhouse situation or any great way to protect trees very much, so I'm going to focus on stuff that "ought" to survive the local conditions.

One of my Kumquats is only protected by a box I slapped together out of a few old windows. I'm pretty sure even a blanket or some plastic would be sufficient on nights where temps drop below 20F or so.
This is a juvenile tree I grew from seed, and young trees are much less hardy than older trees, so I think there is a lot of possibility for success with kumquats in this region.
My kumquat has seen down to at least 10-15F with little to no damage.

Just thought I'd chip in from Northeast Kansas. I had a trifoliate orange planted outdoors at my previous house that had survived two winters while I was there. This past year, checking out the yard from the sidewalk, I see it survived our nasty '13-'14 winter with no apparent damage. We had one three-day stretch where the highs never got above about 15, and the lows hit -12.

I have a Morton Citrange that I'm planning to eventually test for hardiness although I hope to propagate a couple clones first so I don't risk my only specimen. I'm thinking we'll have to have a pretty mild winter, as we did in '11-12 and '12-13, for it to have any chance.

You could try the hybrids with P. trifoliata......US-119, Curafora or Citrangequat could be good choices. Anyway, I think you could grow also "classic" Mandarin, less cold-hardy than Satsuma (but more than lemon or sweet orange), but Tasty.

I've seen lemons grown from seed (random grocery lemons) survive Montana winters. I've heard of one that bore lots of fruit, growing unprotected at that, in Bozeman MT where winter temps routinely hit -30. An orange-grower friend tells me the trick to hardy citrus is own-root, not grafted stock.

Lemons and -30° are two things not compatible

Rez Zircon wrote:I've seen lemons grown from seed (random grocery lemons) survive Montana winters. I've heard of one that bore lots of fruit, growing unprotected at that, in Bozeman MT where winter temps routinely hit -30. An orange-grower friend tells me the trick to hardy citrus is own-root, not grafted stock.

You've seen with your own eyes? For a number of years now I've seen some stories about seemingly impossible survival of lemons and other non-hardy citrus in MT and nearby states,
but frustratingly whenever I try to get to the root of the stories, I can never find any real evidence or confirmation.
I would love to see some pictures or some info about specifically who has done this.

https://permies.com/t/16891/labs/lemon-trees-montana

Amongst all my various cold hardy citrus I've planted outdoors and in my greenhouse, I have one lemon tree that has managed to survive about three years planted in the ground with some protection.
this tree has been burnt all the way to the ground each winter though.

Yeah, we planted lemon seeds outdoors in Great Falls MT -- this was back around 1970 -- and they never got more than a foot tall, but seemed to have no problem surviving, and this was back in the era of really hard winters. I left in 1972 but my sister says they were still alive when my mom moved out of that house a few years later.

They lost their leaves in winter, just like any ordinary deciduous tree, and the little trunks did survive and re-leaf in spring.

Seeds were from random grocery lemons, whatever seeds were already sprouted when we cut one open. I think this started when we ran out of pots to grow 'em as houseplants.

It's been many years since I've seen a storebought citrus with sprouted seeds inside it, and now I wonder how that might relate to hardiness.

Incidentally I once planted an avocado in Great Falls -- buried the seed in October, and lo and behold, it came up the next spring and grew 3 feet tall! But alas, died the next winter. So evidently the seeds are vastly more cold-hardy than the growing plant.

I have little hope for lemons to grow here in zone 7/8 , but I have some substitutes that work where I live: unripe Satsuma mandarins are pretty good lemon substitutes, and trifoliate orange is like a cross between lemon and gin.

I made some trifoliate orange jelly last fall from fruit I collected from my tree, and it's not bad, it's an aquired taste for sure, but it works.

The satsumas have just the minimum protection each winter, and the trifoliate oranges are completely unprotected.

I got some seeds for citrus ichangensis / papedas from a guy in Germany last year and hopefully the little plants I've grown will matiure enough to plant outdoors within a few years.

Try also Citrangenquat "Thomasville"....very cold-hardy, the unripe fruit is more or less like a Lime, when ripen, instead, is sweet

Francesco Delvillani wrote:Try also Citrangenquat "Thomasville"....very cold-hardy, the unripe fruit is more or less like a Lime, when ripen, instead, is sweet

Some more info on various crosses:
https://hort.purdue.edu/newcrop/morton/sundry_hybrids.html

https://hort.purdue.edu/newcrop/morton/lemon.html

(looks like the whole book is online)

"'Genoa'–introduced into California from Genoa, Italy, in 1875. Almost identical to 'Eureka'; ovoid or ovate-oblong with blunt nipple at apex; base rounded or slightly narrowed; of medium size; peel yellow, medium-thick, tightly clinging; pulp in 10-12 segments, melting, medium-juicy, with 29 to 51 seeds which are light-brown within. Tree is shrubby, nearly trunk-less, spreading, very thorny, cold-hardy. Grown commercially in India, Chile and Argentina."

I just discovered that I have a "Surprise Lily" in my front garden; this is not supposed to be cold-hardy below zone 6 or rarely zone 5, but I know it's been there at least 5 years and probably a lot longer, and two years ago we got to -30F. (Also read of some surviving in Minnesota.) Anyway now I'm thinking my front garden, where everything but irises (and this lily) struggle, might be just the place to try a hardy citrus -- might be enough thermal mass in the surrounding concrete to keep roots alive. Also had some annuals survive in the driveway garden -- between a rock wall and a concrete driveway, and it never did really freeze hard there last year (also gets snow piled high which is great insulation). So that's another spot I'll have to try. Worst thing that happens is nothing!

Cris  How are your seed grown kumquat trees .  I hope they have they fruited for you.  I have 1 seed grown Fukushu kumquat tree in ground  for 22 months that gets a window box over winter.  I have 5 seed grown 14 month old Meiwa kumquat trees I plan to put in ground this spring.  

My kumquats got bitten pretty bad last winter, it looks like they will recover though.  None of those have fruited yet, I may have to be more agressive with the fertilizer this year and get some more growth out of them.  The more mature the trees are, the better they survive the winter.