I have five hydrangeas in my yard. One I recently purchased, Oak leaf. Another I dug up from a house that was about to be bulldozed down and two smaller ones that I have had for many years. The rescued hydrangea is big and blooms without any help from me. The oak leaf, even though it is still small, blooms very well. But the other three have maybe one bloom, if any. They are on the northeast and northwest corners of my home. What am I doing wrong?
This article will help:
How do I prune the Oakleaf Hydrangea?
This article should help you with that: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/prune-hydrangea-bushes-hydrangea-pruning-instructions.htm
Last year I 'tried' to root an Oak Leaf hydrangea cutting. It just didn't happen, even with rooting hormone. I now have another cutting. Since the 'stem' is rather woody on the Oak Leaf, can you tell me the best/easiest way to root these?
I would try again with traditional rooting methods. Even the best professional gardeners do not have a 100% success rate. Keeping humidity up around the cutting it key to success though.
Honey is not a rooting hormone like willow water, but it can help in rooting cuttings. It is anti-bacterial and helps to keep disease away from the open wound on the cutting, which means that the cutting will have a better chance at rooting.
What type of soil is under an evergreen tree? I planted an oak hydrangea around the tree and it is dying. There are a lot of needles on the soil from the tree. Should I move the plant?
The soil under pines tends to be high in acid. But more likely, the tree is using up all the water in the area and this is what is killing the plant. This is common. It would be probably best to move it.
My hydrangea has black spots all over the leaves. What is this, or is it normal?
It has fungal leaf spot. Control options include cleaning up and disposing of any fallen leaves or removing those still on hte shrub to prevent spreading. Avoid overhead irrigation, which wets the leaves, and use drip irrigation, soaker hoses or a watering wand instead. It is helpful if your oakleaf hydrangea is planted in an area where there is good air circulation. Make sure it is not crowded by other plants. This permits the leaves to dry quickly after rain, which helps prevent leaf spot diseases. You can also apply a fungicide.
I have several plants - Oakleaf hydrangea, black-eyed Susans, and coneflower - where the leaves have holes in them and may also have rust disease. The plants are growing, but they do not look very healthy. I am unable to find any information on treatment. I have tried water and soap, but it does not appear to help. I have not tried soap, oil and water, which was my next option. Removing the damaged leaves would leave the plant almost bare.
This article should help with that: https://www.gardeningknowhow.com/plant-problems/disease/learn-about-plant-rust-disease-and-rust-treatment.htm
I've got an oakleaf hydrangea and a smoke bush which both grow huge and healthy looking each summer, but neither has flowered for over 10 years (they were planted 11 years ago). I prune them back in late fall. What can I do to get them to bloom?
I would suspect that they have too little phosphorus, especially if they are planted near a lawn area that gets regularly fertilized. This article will explain more: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm