Can i help my fortunella?

[stefs]

I am from Montenegro (europe), this winter is very hard. Not snow, but temp is about 0C.
My fortunella is looks different, can i help my plants?

[Millet]

First flex the small and medium  branches to determine if they are still flexible, and have not become brittle and  dried out. Using your finger nail or a sharp knife, scrape off a small piece of bark in several locations of the tree to see if the cambium layer is still green in color.  If both are OK your tree could leave out next spring.  If the tree's branches are dried brittle, and you can not locate any green cambium then it certainly does not look good for the tree.  In any case there is no hurry to remove the tree.  Wait until spring for any possible growth to determine what course of action you wish to take.

[stefs]

can i help my plant in any way?

[Millet]

Your tree has been damaged, and there is no green foliage to generate energy for the tree .  Therefore, the tree will have to recover using the reserve energy from last season.   You should protect the tree during future cold spells, and wait for spring to see if it recovers. There is not much else you can do.Good luck

[Citradia]

Stefs, have you had many nights below 0 degrees C?  A fortunella/kumquat should be able to handle some freezing weather in winter. How many hours below freezing has it endured?  Make sure it is well watered before a freeze, and if possible, cover it with frost cloth or make a frame around it with pvc pipe and cover it with 4 mil plastic sheeting and can even heat with space heater or light bulb if need be to prevent prolonged period below freezing and subsequent damage. I'll try to post some pics of my pvc frames. Just remember to uncover the tree during the day if temps get into 50's F so the tree doesn't break dormancy before threat of freezing temperatures is over.

[stefs]

In my place this winter temperature is be above 0C, maybe -1,-2 but this is max. I have a snow, but this is lasted only for 2 days..

[Laaz]

0 C  (32 F) is nothing to kumquats, you have something else causing your problem. I have multiple trees in the ground that have taken low 20's F and not dropped a leaf.