I am interested in this as well. If that is true, then I can plant one outside here....

The best rootstock for marumi kumquat would be (Flying Dragon) Poncirus Trifoliata. Nature Hill used C35 (citrange) as rootstock which is not reliable in zone 8. They should have used FD rootstock to fully dwarf the tree and to increase cold tolerence of the root.

It is also probable that the kumquat is not compatible with C35 and will die early as a result.

Steve

poncirusguy , right, I contact Nature Hills and asked them to verify their Marumi Kumquat rootstock, they responded that it was C35 trilofiate. I did not find any reliable source to get a marumi tree to experiment with. I don't know where to search for some seeds to start. Citrus viruses from scion woods could kill our rootstocks as well.

"They often don't show any damage even when the temps get down to 10 degrees. At 0 degrees they will lose their leaves, but by spring, the leaves will grow back! "

NOT ON C35. Grown only on PT or FD may give you that cold protection.

Steve

Laura LaRosa (7b) , try citrangequat, at zone 7b if you have a matured enough citrangequat, it might survive outside at your zone with little to no protection.

poncirusguy , I am confuse about that statement. I remember I have seen it somewhere, from a article; however, I doubted that because that the only source to claimed Marumi as most hardy. All other sources did not mention any specialty of Marumi. I hope this myth about Marumi is true. since their leaves were smaller than other Kumquat types, I guess it might be the most hardy one in the kumquat family.

I think what Steve is saying that even if Marumi is hardy down to 0*F, the C-35 rootstock won't be, and the tree would die as a result.

Does anybody Really know if a Marumi is cold hardier than a Meiwa or Fukushu or Hong Kong peanut sized kumquat anyway? You can get actual FD or PT seedlings from edible landscaping cheap enough and save a step......4 winds carries a Marumi and if you call mayb eyou could get a custom graft job...don't know or graft later

Anything from that TYTY nursery is .......taken with a big kosher grain of salt

Tom You are correct. only PT, FD, and US842 will go down to 0F and only the PT &FD will go colder. Marumi is used for dwarfing rootstock so planting from seed is a good option. C35 might reach 10F. The PT & FD are deciduous and push an extra 5F lower.

Swingle citrumelo is good to 10F.

Meiwa on PT

bklyn citrus (zone 7B), at this moment the myth of Marumi as the most cold hardy kumquat was lacking of researches as well as evidence; however, we can try ourself to verify that. I will buy a marumi from Four Winds just to get the wood scion from it to graft on my FD rootstocks. I hope their tree won't come with diseases. I read their feedbacks, horrible, lots of complaints about diseases, low quality trees...

Pictures!!! please

bklyn, thank you for that info. I have more confidence from your guarantee, lol.

Some citrus viruses don't even show up until years later especially when the tree get weaker from stress or from age.

I posted pics of tree and fruit before, not handy now, but I'm happy with the purchase

This Seville seedling was 7 months old when Loa and I grafted it with the NZL scion.

New Zealand lemonade on Seville sour orange · More Info

Now 4.5 months old from bud sprout.

New Zealand lemonade on Seville sour orange · More Info

US897 seedling around 8 months old when grafter with NZL

New Zealand Lemonade on US897 grafting · More Info

2 years 8 months later.

New Zealand lemonade on US897 rootstock. · More Info

10-xx-2018 The fruit at the top grew fast until the tree flowered putting on up to an uncountable 500 flowers. It dropped its fruit and some leaves. I removed all the flower and left 5 fruits. They to dropped

Your Flying dragon should be graftable in 7-8 months. Give them loots of light.

5 meiwa seedlings grow at the same rate as marumi seedlings grow

Meiwa · More Info

Under a bucket light.

Meiwa · More Info

6 months old

Seedling Meiwa kumquats 1-9 · More Info

Steve

Steve, try Keraji or Sanford Curafora, they were said to be extremely hardy and somebody claimed that they are as hardy as Citrangequat. Keraji and Curafora both are sweet!

Sanford Curafora is killed at 18F to 10F and the keraji no info

We have been experiencing cold hardy zone shift over many decades. I live in Atlanta which was listed as in zone 7b/8a, but I am pretty confident that Atlanta now should be in zone 8a and in the next 20 years could lie in 8b.

4 winds Fukushu, its holding some small fruit and coming into bloom again

bklyn, is Fukushu more cold hardy than Meiwa?

I still wonder between Nagami and Marumi which one would win the crown?

I have no idea as I grow it in/out in a pot. It appears to be hardy with its stouter rounded leaves, I really doubt there's a big difference between the two According to territorial seed: Fortunella obovata Fukushu is a naturally small tree with a spreading habit that makes it an attractive ornamental shrub. The leaves are broader and fruit larger than other kumquat species. At 1 1/2 inches long, the oval fruit boasts thin, sweet, edible rind with tart, acidic flesh and few seeds. It's an especially hardy variety that can withstand temperatures as low as 28°F without protection. When I tasted the fruit, I thought the peel tasted like apple non descript, and the inside was sweet/sour like an orange, not terribly tart.

I read about cold hardy citrus on wiki, and found that Kumquat could withstand down to 10F with no injury. You live in zone 7b according to the old map pubished in 2012 based on temperature from 1976-2005, and your zone now should be very close to zone 8a due to cold hardy zone shift. You should graft a branch on FD roostock and try the outside with little protection and when it's been matured I believe no protection needed.

I am in Atlanta, zone 7b as well according to USDA zone map 2012. I believe my area is actually in the border of zone 7b/8a.

I would be extremely surprised if it could survive in zone 7, in fact I'd bet money on it. (that it would not)

However, I have read at least one report of kumquat surviving in Seattle outside in a protected location. (and by 'protected', I mean the plant was still exposed, it was just planted in an ideal warm spot) That's still zone 8 though.

I remember reading the results of one field trial that seemed to show kumquats did not seem to be able to survive as well as the temperature ratings might lead one to believe. Many of the other hardy citrus cultivars survived where the kumquats all died.

It is true however that kumquats are the hardiest of the common citrus.

If you're around Dallas it may be worthwhile to try experimenting growing kumquats outdoors, but if you're in Atlanta I wouldn't bother.

One Green World nursery recently acquired some seeds of a hybrid kumquat that may be able to survive zone 7, so look for that in the next couple of years.

Socalnolypia, I have Thomasville Citrangequat is a Kumquat hybrid as well, and I know for sure it has no problem growing in Atlanta outside unprotected when it has matured enough, of course in a ideal spot against the south or east wall of the house.

If we talked about Kumquat hybrid between the 2 slighty hardy citrus, the off springs were usually less cold hardy compared to their parents!

Atlanta winters have been pretty warm and stable for the previous 34 years.

https://www.currentresults.com/Yearly-Weather/USA/GA/Atlanta/extreme-annual-atlanta-low-temperature.php

Here is Dallas - Lowest Temperature for Each Year

https://www.currentresults.com/Yearly-Weather/USA/TX/Dallas/extreme-annual-dallas-low-temperature.php

By comparing the 2 reports from Atlanta and Dallas, we can see that in the last 10 years the lowest temperatures in 2 states were not much different. Dallas was not always warmer than Atlanta. By the year of 2011, 2013, 2016, Atlanta was warmer than Dallas and by 2017 both were tied at 15F in lowest winter temperature records.

I would not grow outside in 7A either with out a real shelter setup. Every 5 years a zone 6b front will swing through and kill your 7a trees. The duration of cold will dessicate your trees before the roots wake up to provide moisture. If you are going to grow in 7a you will need a

A closeable party tent. This one $69 + tax will hold 2 full grown Fukushu kumquat trees on Flying dragon.

My setup

Four layers of low-E glass

Steve, they look so nice though.

I live in Atlanta (zone 7b) right at the border of zone 8a. In the last 34 years the lowest record of Atlanta winter was 6F for a short duration, and only dropped down to a single digit every 10 years. And single digit temperature might never happen here in Atlanta again because it keeps getting slightly warmer little by little every year.

https://psmag.com/environment/why-is-winter-suddenly-so-warm

I am about to verify the myth about Murami Kumquat. If this myth is true then my marumi grafted on FD should survive without protection outside in my zone area.

Good read. Any updates?

Huyen Linh Ho Unfortunately I did not see this until today. The answer is yes. You will need to set up framing around your tree or get a floorless party tent that can protect your tree for the worst. Flying dragon is the only rootstock that should be used. C35 will die.