How fast do these grow and how tall?
Japanese boxwood generally reach 4 feet tall and wide. They grow at a slow rate of about 12 inches per year. Of course, size will vary depending on the variety.
I am looking for a plant that does not grow taller that 3-4 feet. This plant will be near my front door.
They will not be very picky about their neighbors. You have a clean slate to work with, essentially.
I would advise planting for all seasons, to make best use of your space.
This article will offer some suggestions, as well as link to other articles with even more suggestions: https://www.gardeningknowhow.com/special/spaces/designing-four-season-gardens.htm
Last spring I noticed some spots in our boxwood hedge that were stressed and dying. This year the area has spread. What could be causing this and what would be the best treatment? The area loses all leaves and leaves bare areas in the middle of the hedge.
It could be boxwood decline. Here is a management article.
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/treating-boxwood-decline.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/diseases-affecting-boxwoods.htm
My boxwoods accidentally got burned with fire. One bush was engulfed and the other two were half burned before we were able to douse with water. Are they dead or by any chance will they come out of this?
Unfortunately, your photo did not come through. Many times, these shrubs can come back from the root, just fine. This is even true with serious damage.
They may take a few years to be back to shape, but they will likely survive.
Here is an article that will help you to provide the best care to ensure that they have the best chance of return: https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-care.htm
Unfortunately, your photo did not come through. Many times, these shrubs can come back from the root, just fine. This is even true with serious damage.
They may take a few years to be back to shape, but they will likely survive.
Here is an article that will help you to provide the best care to ensure that they have the best chance of return: https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-care.htm
Box hedge 9 yrs old. Last year looking a bit weary. This year seriously leaves dead. But shoots and stems still alive and green on inspection caterpillars green and black striped curled up in all the leaves Do I cut back to 10” high and spray caterpillars Or dig them up Plant new. But will the caterpillars be in the soil or surrounding plants and come back
It may be the dreaded boxwood tree moth. A Bt type spray seems to be most effective. The moth lays eggs on the plant so it is not in the soil. Here are some other insects that plague boxwoods:
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/controlling-boxwood-insects.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/prevent-caterpillars.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/using-bacillus-thuringiensis.htm
Shade tolerant boxwood or any shade tolerant shrub?
You have quite the number of shrubs to choose from, here!
These articles will help:
https://www.gardeningknowhow.com/special/shade/evergreens-for-shade.htm
https://www.gardeningknowhow.com/ornamental/shrubs/shgen/shade-loving-shrubs.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/common-boxwood-varieties.htm
I recently treated my boxwoods with a horticultural oil spray. Now I am seeing significant yellowing of the leaves. Is it possible this yellowing is caused by the dormant oil spray? And will this cause significant, long term damage?
Yes, this is very possible if this was done while it was sunny out. The instructions will suggest not spraying in sunlight for this reason. It is also best to test on a very small portion of the plant to ensure that there is no negative reaction. Depending on the strength of the dormant oil, it is possible that the mix was not diluted out enough, as well. Generally, this is not used on plants that do not experience a true dormancy, such as boxwoods, unless specifically stated for use outside of dormancy.
Unfortunately, the damage is done. Once the leaves fall off, it will likely recover on its own. If it doesn't recover as nice as you would like, then trimming it will help bring it back.
This article will help:
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm