This will be the third time this holly bush will be moved. Can it be done without harming the bush? What will insure it surviving another move?
It can survive. The trick is to reduce stress to the plant as much as you possibly can. This article has some tips on that:
https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm
You may also want to prune the shrub back some to reduce the amount of leaves the smaller root system will have to support.
We have 18-year-old Holly bushes (about 10 ft. long, 4 ft. wide, and 4 ft. tall) in our front yard and they seem very healthy. We had two spruce trees on each end of these bushes. We have decided to replace the spruce trees with new Holly bushes. My question is, should we pull out our 18-year-old holly bushes and replace them with new ones or are there still a few years left in their life span? How long they are supposed to live?
Don't pull the plug on your holly shrubs just yet. They will actually outlive us, provided they remain healthy. Their typical lifespan is well over 100 years.
I know that female holly bushes have red berries, but why do some bushes have just green berries. They have been on my bush for months and are not changing to red. Never knew this could happen. Why?
It sounds like your plants are affected by holly berry midge. These pests lay their eggs inside the holly berries and, to preserve the eggs and larva, release a chemical that prevents the holly berries from turning red. This article will help you learn more:
http://www.upenn.edu/paflora/plantclinic/hollyberrymidge.htm
A portion of my holly bush looks like it died and there is a small portion of the bush alive. Should I prune the dead portion now and how should I keep the live portion alive? Should I fertilize the portion?
Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/shrubs/holly/trimming-holly-bushes-how-to-prune-holly-bushes.htm
Holly bushes have black stems, especially on the underside. What is it and how can it be cured? I live in Zone 5, northeast PA.
It sounds like you have sooty mold. This article should help: https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm
I have had holly bush for over a year now. And over the year they get a white powder and little black or dark brown tiny spores from what I have been told. I don't think it's black spot. I have cleared old straw and keep it clean. The bottoms I keep clean and dry. I have used sprays for fungus. What can it be?
The white powder you describe is powdery mildew. Powdery mildew is caused by fungus that attack Holly leaves, sometimes covering them entirely with a thin white powdery coating. For more information, here is an article or two that you may find helpful: https://www.gardeningknowhow.com/problems/get-the-cure-for-powdery-mildew.htm
https://www.gardeningknowhow.com/plant-problems/disease/powdery-mildew-homemade-and-organic-remedies.htm
The black substance sounds like sooty mold, which is a symptom of several kinds of pests that can attack hollies. I recommend treating the plants with neem oil. This will kill any pests on the plant and treat the sooty mold as well. This article will help: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
What is required to winterize a holly bush in Minnesota, Zone 4?
Generally these are hardy plants, requiring little, if any, winter care. However, in extreme situations, the shrubs can be wrapped. Here is an article on growing holly shrubs that you may find helpful: https://www.gardeningknowhow.com/ornamental/shrubs/holly/growing-holly-bushes.htm