Will too much water cause the green leaves to fall off?
It can! There are several reasons why this could happen, though.
Here is an article that will help:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-leaf-loss-in-spring.htm
y this holly bush is close to 50 years old
Unfortunately, your photo did not come through. I will be unable to identify the issue. Likely, the sooty mold will be caused by the insects, or larva that are feeding on your plant.
What I can do is point you to some of our articles that will help you with natural pest control. These will help:
https://www.gardeningknowhow.com/special/organic/what-are-organic-pesticides.htm
Will they turn red? Do I need to do something to care for it?
Your holly berries are probably waiting for some cold weather. If the green berries have been there for a long while, they may be simply last year's berries that didn't mature. I'd wait until December to see if the berries turn red. If they don't, you may want to examine the tree for other possible problems. (Do I see dead branches in the photo?)
This article is all about how to care for holly:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/growing-holly-bushes.htm
https://www.gardeningknowhow.com/ornamental/shrubs/holly/when-does-holly-bloom-fruit.htm
Small 2ft tree in pot had abundance of flowers which turned to berries, and soon dropped off. Bottom leaves are turning yellow and falling. I am now left with tree and 5 lovely red berries.
This article has all the info you need on how to treat your holly tree:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-yellow-leaves.htm
How do I shape my holly trees ? into a round ball. Also the leaves on one of the trees has started to go yellow & drop off. I was wondering do I need to repot or feed the tree. I bought the pair of trees last year & have only watered them.
Round isn't usually the best shape for plants because the lower part doesn't get enough light. Plus, hollies aren't the shrub/tree of choice for topiary shapes. Those recommended are boxwood, yews, dwarf Alberta spruce, and arborvitae.
https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-yellow-leaves.htm
https://www.gardeningknowhow.com/ornamental/shrubs/holly/fertilizing-holly-bushes.htm
https://www.gardeningknowhow.com/garden-how-to/projects/how-to-make-your-own-topiary.htm
https://www.gardeningknowhow.com/ornamental/shrubs/holly/american-holly-trees.htm
My late brother bought me a holly bush ,after 11/12 years it has red berries on for the first time ,having white/cream ones in all previous years ,could you tell me why. Please
This won't be very common but can happen with a grafted Ilex. What does, sometimes, happen is a shoot from a grafted rootstock will take over. When this happens, the scion (or top) may fail, but the rootstock can continue on.
https://www.gardeningknowhow.com/ornamental/trees/tgen/grafting-trees-what-is-tree-grafting.htm
We have a 15 year old holly hedge that needs about 18” taken off of One side of it. When is the best time and best technique to do this in Zone 9?
This article should help: