Can Eugenia be kept in plant containers and put on top of rooftop to screen neighbours ?
Yes, I think that this is possible. This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/shrubs/eugenia/growing-eugenia-plants.htm
I'm attempting to grow new Eugenias in a shaded area...trying to fill in an area where there are currently Eugenias, but they were planted 30 years ago when there was full sun in this area. Has anyone had luck growing Eugenia hedges in shade? Thanks...
For an area that receives part shade to part sun, try surinam cherry (Eugenia uniflora), hardy in USDA zones 9b through 11.
You could likely do well if you have morning sun and afternoon shade.
https://www.gardeningknowhow.com/ornamental/shrubs/eugenia/eugenia-hedge-care.htm
The 10-10-10 is just a general recommendation. What you found is fine or a complete organic fertilizer works well, too, and lessens the chance of burning.
I purchased 2 Globulus Topary Eugenia last spring (2019) and planted them myself. They were beautiful all summer long. I had to trim them to retain their shape 3 times during the year. They both turned brown this winter and I thought maybe that was normal dormancy but they don't look like they are budding at all and most of the info I'm getting online imply that they don't turn brown during the winter at all. Now I'm wondering if they are dead. Now that I'm looking at the picture I'm sending I'm sure you are chuckling and saying "Yep, that's dead". Thanks for any comments besides that one. :)
These small shrubs are, almost exclusively, tropical. They cannot tolerate temperatures dipping down below about 25 degrees. Because of this, they are typically grown in containers for the duration of their lives. The winter has killed them.
Now, let's address the second thing- They are grown in container, usually, so that they can retain their topiary structure. Retaining the shape, often, requires root pruning. For this reason, keeping one in this state will be much easier in container.
If you choose these for an outdoor shrub, it will be best to keep them in container to move indoors over the winter. It will be easier to maintain this way, as well.
Here is an article that will help you with the care of the shrub: https://www.gardeningknowhow.com/ornamental/shrubs/eugenia/growing-eugenia-plants.htm
I have several eugenia trees that are 15 feet high with no foliage in the lower 5 or 6 feet. Will they sprout new foliage if I cut them to 2 or 3 feet. They were never pruned and I would like a lower screen than they provide.
They tend to tolerate heavy pruning just fine!
These articles will help:
https://www.gardeningknowhow.com/ornamental/shrubs/eugenia/eugenia-hedge-pruning.htm
https://www.gardeningknowhow.com/ornamental/shrubs/eugenia/growing-eugenia-plants.htm
Wondering if the roots will get big enough to lift concrete
As long as you give 1 or 2 feet of space between it and the concrete, you will likely never see an issue with it. Any closer, and over time it could be lifted by the larger roots near the surface. This would take a very long time, though.
For some care tips on this shrub, read these articles: https://www.gardeningknowhow.com/ornamental/shrubs/eugenia
I am looking for a small leaf hedge that I can plant along a fence that separates my yard from my horse pasture. I will not let it grow over the fence but just to be on the safe side I want something that is not toxic to horses. Ang suggestions would be helpful.
Globulus Eugenia does not appear on the ASPCA's list of plants that are toxic for horses. Here is an article from Penn State University that mentions a few different trees that could be toxic to horses. I hope this helps:
https://extension.psu.edu/plants-toxic-to-horses