I have some well established holly shrubs on the north side of my home. This year all five of my plants show no live growth on the side of the plant nearest the building. Will this come back, or should I trim all of the dead growth away?
Yes, you can go ahead and cut away all of the dead growth. Give it some time and the leaves should regrow.
What makes holly leaves to all turn brown and die?
It is difficult to say for sure. There are a few things that can cause this. Holly scorch is the most common. This happens when the weather changes too quickly. The plants should recover from this on their own. Usually brown leaves signify that they need more water. Give them a good dose of fertilizer to help them get back to full health. Using root stimulator solution on the plants once a month for at least six months may help too, provided that the issue is not root rot. Another possibility could be holly leaf spot. Here is an article that may help: https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-problems-holly-leaf-spot-or-holly-tar-spot.htm
If the bark is still green, the plants are still alive, and even if they lose all or the majority of the leaves, they should eventually leaf back out.
I have both male and female bushes. The females used to have berries. They don't anymore and I don't see flowers. Why?
There are other reasons a holly might not have berries. This article will help you with that: https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-bush-no-berries.htm
Recently some parts of my 15-year-old holly shrubs (about 3 ft high) have been dying out. On other holly shrubs (I have a total of 6), there is a white substance on the underside of leaves. Last fall, and again this spring, I applied Holly Tone but perhaps not in enough quantity. I love the holly shrubs and want to save them.
It sounds like you may have pests, perhaps scale or mealybugs. I would recommend neem oil. I have found it to be very effective against these pests. Here is more information on it: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
We have two in the backyard and they are not doing very well. Basically, both trees have dead leaves. Many of them started growing green, but very soon the tip of the leaf begins to dry out and it turns brown until the entire leaf is dry, brown and dead. The branches are green, but on the tips they are turning black and eventually they dry out too. We have had these trees for many years, but this is the first time it has happend. We don't know what to do and we don't want to pull them out if we can avoid it.
There are a few things that can cause this, with holly scorch being the most common. This usually happens when the weather changes too quickly. The plant will normally recover from this on its own. Are you seeing any other symptoms? That will help us pinpoint it better.
Our neighbour has a holly tree, next to our border line. We wish to lay paving in this area, but roots of the holly tree are there. If we cut them, will the tree die? The tree's leaves are yellowing at the moment. Thank you
Yes, removing the roots near the soil line may kill the plant. It may also survive. It is about a 50/50 chance.
If the leaves of the plant are yellowing, then it is possible that something else is already affecting it. This weakened state would increase the chances that removing the soil line roots would kill the tree.
I had my holly berry trees 7 years and the leaves have black spots under the leaves and when new leaves come out they turn to black spots and some white spots.
You have a fungus called black spot. This article will help:
https://www.gardeningknowhow.com/plant-problems/disease/black-spot-fungus.htm