I have two large holly bushes that had considerable deer damage done to them this winter. Can I trim now (in the spring), and how far back should I trim them? The front half of each bush is completely stripped of leaves.
Yes, you can prune it back, but you won't get any berries this year. You can cut the shrub back by a third without harming the plant.
I have a holly hedge that has small, white, rice-shaped deposits on the back of leaves. It looks like someone took paint and splattered it all over. It is most noticeable on the darker, older leaves, but is also on new growth. I have four other hollies in the yard, and they too are infested. There doesn't appear to be anything moving--mites, white fly, etc. But I am wondering if these are egg sacs or deposits for future infestation.
It is likely aphids. They don't move much. This article will help you:
https://www.gardeningknowhow.com/plant-problems/pests/homemade-aphid-control-a-natural-way-to-kill-aphids.htm
Neem oil is an effective treatment for these pests. Here is additional info: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My holly bushes do not look healthy and have thinning leaves and some are yellowish. Do I need to put a particular fertilizer on them, or does the ground need to have a certain acid content or does my dirt have too much acid?
Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-yellow-leaves.htm
What is the maximum distance a male and female holly plant can be planted and still guarantee proper pollination?
You can plant them pretty far apart and still get berries. Some sources say to plant them within 100 yards, while others say up to 300 yards.
I just pruned my holly bushes. Can the clippings root again in water and then be transplanted to a container to create another holly bush?
This article will help you:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/propagation-of-holly-shrubs-with-holly-seeds-or-cuttings.htm
I moved into our cottage 5 years ago and there was an established Holly bush, which looked very healthy, but over the years I have seen it lose its leaves. Last year it lost quite a few but this year they have practically all dropped off. If you touch a leaf or the wind blows, they just drop off. Is there anything I can do to counteract this?
Here is an article that you may find helpful in determining the possible problem: https://www.gardeningknowhow.com/ornamental/shrubs/holly/diseases-of-holly-bushes-pests-and-diseases-damaging-holly-bushes.htm
Had holly bush for 6 years, but leaves have been falling off since heatwave at Easter this year. Mostly green leaves and a few brown. HELP.