Buy all of the above? ;) You may want to clarify the following: Are you planning on planting these trees in ground outside or in containers that could be taken inside?

I'm planning on planting them in the ground and protecting them for the first 4-5 years and after that protecting only when it goes bellow 24 degrees Fahrenheit .

You write " enjoyable to eat out of hand". In MHO only two would "qualify" as enjoyable - the two Limequats, and then only if you enjoy eating sourish fruit out of hand.

John they aren't on my list because I already have them:)

Ps does ur kumquat ripen without any problems?

Ah, glad you already have those! I'm not sure what kind of problems you may mean but my kumquats ripen as I expect them to. Just about now, they are beginning to orange up and I have actually eaten a few of the ripest ones already. I think enough will be ready in another week or two so I can pick enough for a pie. I eat a lot fresh off the tree.

Nippon will do well in those zones. I have no knowledge of the others.

6b Steve

Thanks steve , definitely getting him.

John sometimes the fruits on my kumquat just stop ripening in december and then in spring they start ripening again.

I didn't recognize any of the standard picks of cold hardy citrus on your list. Harvey lemon, arctic frost and orange frost satumas, Thomasville Citrangequat, Meiwa kumquat, Nagami kumquat. Any of these grafted to Flying dragon would do well in your area. Some grafter graft dwarf trees ton Flying dragon. I have 4 Poncirus Trifoliata trees, the full size flying dragon, Growing in very heavy clay devoid of organic matter and all 4 are doing exceptionally well.

6b Steve

Here is what is said by the Southeastern Palm Society (which also does a LOT of work with cold hardy citrus varieties) about the Nippon Orangequat .

Nippon Orangequat - (Fortunella crassifolia X Citrus reticulate) is a cross between the Meiwa kumquat and the Satsuma Mandarin orange. The resulting tree is very cold hardy and specimens in protected sites have easily withstood upper single digits with no protection. Characteristics are intermediate between the two parents, the egg shaped fruits are bright orange inside and out with an edible peel. They're sour and juicy making an excellent marmalade and drink. Nippon orangequat bears reliably and abundantly under southeastern conditions and rarely fails to make a crop. The plant is fairly low and spreading, reminiscent of Satsuma, with large pointed kumquat like leaves. It makes a very handsome ornamental plant and is hardy to at least 10F.

Flavor: Sour tangerine, no off flavors, good quality.

Use: Juice, preserves

Note: Becomes sweeter as season progresses, but fruit must be over wintered to become sufficiently sweet to enjoy out of hand.

Thank you silica,if they become sweeter as the season progresses can I leave them on the tree until spring comes or will the frost ruin them.

Steve why do they need to be grafted onto the flying dragon I want to have full grown trees the flying dragon is a dwarfing rootstock isn't it?

In your case for a full size tree then Poncirus Trifoliata would be a good choice. The Poncirus Trifoliata and its mutated cousin Frying dragon push extra sweetness into their fruits. The Nippon Orangequat will need all the help it can get. These same 2 root stocks also increases the cold hardiness by up o 5 degrees colder. Other choice may need all the help they can get can get. Fruit is destroyed below 25F and can be damaged below 28F. The most important choice for you is to grow trees that ripen their fruits before the fruit destroying temps hit your area. If you are in sandy, or calcium soil then PT or FD will not work.

kos, yes you can leave the fruit on until spring, but if your area receives severe weather , as poncirusguy wrote, you would need to protect the fruit.

A Nippon on Flying dragon will be very productive and very easy to protect even when full grown. I also apply light to my kumquat trees in early spring so they flower 3 months early and then the fruit is ripe and picked by the time my cold comes in. 3 23 watt CFL spot lights for 3 weeks would do it for an 8 foot tree.

Silica thankfully I don't have sandy soil so I can use them as rootstocks but I think they will not have problems in my 9a climate since my neighbour has a kumquat that never has damaged fruit.

Steve I don't understand what type of light do u apply? The citrus in my area usually flowers in april is that early enough?

That is early enough. However I thought kumquats flowered in late June. If so, added light in April would give the feeling of late June and give your tee a 2 month head start. your 9a-8b is 25F warmer than my 6b/6a. You probably won't have a problem with loosing fruit to frost.

From my experience the kumquats in my area have ripe fruit in late summer and then they flower again in the fall.

I hope the frost won't get them if it doesn't get the grapefruits it souldn't get the kumquats either.