Gnom grows straight up and stays narrow, reaching 10 to 12 feet tall and only 3 to 4 feet wide, with delicately textured gray-green foliage striped with silver. Juniperus communis 'Gnom' grows in full sun, hardy from Zone 2 through Zone 8.
It puts on about 3 to 4 inches a year, so it takes a long time to reach full height. That slow rate is what makes it usable in a small space or a container, where a fast columnar conifer would outgrow the spot in a few seasons.
The branching is strong enough that it holds its shape under snow load rather than splaying open, which is the failure mode that ruins most narrow junipers in a hard winter. Blue berries persist on the plant through most of the year.
Zone 2 hardiness puts it further north than nearly any evergreen. It wants full sun and excellent drainage, handles drought, salt, and poor soil, and will not tolerate wet ground. Deer leave it alone. Keep it away from apples, crabapples, and hawthorns, since junipers host cedar-apple rust.