Is the fothergilla shrub deer resistant?
Unfortunately, no it is not.
This article may help you: https://www.gardeningknowhow.com/plant-problems/pests/deer/deer-resistant-plants.htm
When should you trim Fothergilla
You really shouldn't. At all.
If you must prune, it will be best done after flowering, or before buds develop for next years flowering.
Here is an article that will help you to care for the shrub:
Where can i get it?
Unfortunately, we do not recommend places to purchase. I would say that you could try your local nurseries, or online. We can offer information on the plant, though:
We have a Farthergilla dwarf that has turned into a beast. We need to cut it back severely. If it dies that solves a problem, though we would like it to live in a smaller scale. Can we cut it down to 1 foot (it in now over 4 feet). and will it survive. I would say it is about 8 years old. Thanks for your help. George
It isn't recommended, as it will destroy its shape, permanently. It may not kill it, though. Ultimately, you may need to remove the shrub if it is not in a good location.