I have a jasmine vine that grows on my deck railing and was hit hard by the cold this past winter. A lot of it is dead. Should i cut it back to three feet from the ground?
You can prune out the dead growth. You may also prune 3 feet from the ground. Just be aware that, depending, on whether yours is a summer blooming or winter blooming, you could affect the flowering this year, but it would help it with the over-all recovery.
This article will help: https://www.gardeningknowhow.com/ornamental/flowers/jasmine/trimming-jasmine-plants.htm
Could you give any advice on the care of jasmine house plants with larger blooms?
Yes, this article will give you information about the care of these: https://www.gardeningknowhow.com/ornamental/flowers/jasmine/growing-jasmine-indoors.htm
should I have pruned these in the fall? Or now? I did neither so far and wonder whet to do. I will take photos tomorrow if you need.
These two articles will help you:
https://www.gardeningknowhow.com/ornamental/flowers/jasmine/trimming-jasmine-plants.htm
https://www.gardeningknowhow.com/ornamental/bulbs/turks-cap-lilies/growing-turks-cap-lily.htm
As above
This article will be a good starting point: https://www.gardeningknowhow.com/ornamental/flowers/jasmine/growing-jasmine-indoors.htm
I have one that is about 20ft long and 8ft tall and 5ft thick, can I use an electric pruner to cut it. I don’t want to damage it, when I have hand pruned it bled a white sap if I use the electric one could it bleed to much sap and hurt it?
It can be a mess, but it will not hurt it at all. This can be a good way to rejuvenate the plant.
Is Miracle Grow a good product to feed confederate jasmine?
This can be ok if it is well balanced. It is always best to top dress with compost and dolomitic lime instead, but feeding it at half strength every couple of weeks will be ok too.
This article will give you more information: https://www.gardeningknowhow.com/ornamental/flowers/jasmine/how-to-fertilize-jasmine.htm
Will jasmine grow in northern Arkansas Marion co
There are some varieties of Jasmine that can grow in zones 6, so pretty cold.
Here is an article with more information on choosing the correct plant.
https://www.gardeningknowhow.com/ornamental/flowers/jasmine/winterizing-jasmine-plants.htm