How far does the root system extend for sky pencil hollies? I have a 14-inch wide area between foundation wall and parking lot. Will the roots impact the foundation?
Sky Pencil Holly does not have an invasive root structure. They can even be grown in containers.
It is recommended to plant 5 feet from a home structure, this is a general guideline for most foundation plantings.
https://www.gardeningknowhow.com/ornamental/shrubs/holly/care-of-sky-pencil-holly.htm
When is the best time to transplant sky pencil holly? They are about 7-8' tall.
Early spring would be the best time.
Here is a link with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/holly/transplant-holly-bushes.htm
The shrub has patches of dry leaves that looks like disease or insect.
Here is a link that lists common problems with Holly.
Trim away the dead and diseased material and dispose of. Clean any plant material from the ground also.
I would treat with Neem Oil. This works as both an insecticide and fungicide. It is safe for people, pets and bees.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My Sky Pencil leaves turn yellow. Also, how often should I water them?
2 inches of water per week.
Here is a few links that will help you.
https://www.gardeningknowhow.com/ornamental/shrubs/holly/care-of-sky-pencil-holly.htm
https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-yellow-leaves.htm
Is Sky Pencil Japanese holly dangerous to dogs if they eat it?
I would classify the Japanese Sky Pencil as poisonous to cats and dogs. The leaves and berries of the Japanese Sky Pencil are mildly poisonous and will cause vomiting and diarrhea if ingested.
My sky pencil holly is on the east side of house, planted approximately 9 months ago. In last couple weeks, it has started turning brown and some shoots look to be dying. Soil is moist down 10 to 12". Any suggestions?
Verify the planting and growing conditions needed in the link below.
Make sure that the soil is well draining.
If you have applied mulch, pull the mulch back from the trunk by 6 inches.
I'm not sure on what growing zone you are in, but in zones 8 and 9, the Holly will need an afternoon shade location.
https://www.gardeningknowhow.com/ornamental/shrubs/holly/care-of-sky-pencil-holly.htm
I have two "Sky Pencil Holly" in 15-gal planters. They get direct morning sun (Willow Park, TX). They have never done well. Neither is doing well, with leaf yellowing and loss and some dead stems. What pH and soil moisture levels are best for them? Is there anything that is critical for growing this variety of Holly?
This plant prefers acidic soils between pH 5 and 7. The problem could be a nutrient deficiency, perhaps exacerbated by incorrect pH. These articles may help you:
https://www.gardeningknowhow.com/ornamental/shrubs/holly/holly-yellow-leaves.htm
http://extension.illinois.edu/focus/index.cfm?problem=chlorosis