This tree is a native of the mountains of cnetral Europe. It's needles are stiff, in pairs, dark green and about an inch long. There are many varieties of the Mugo, which makes them hard to classify.
Roots are slow growing.
Do this from early spring to late summer. The best advice is to take what you want off the top but not much from the roots. New shoots may be reduced by half or more in spring. Don't over-water but don't allow soil to dry.