There is an old yew at the house I bought, growing in full sun. It is already ~2.5 m high and about 6 ft wide. The new shoots in spring are very bright green and at least 10” in height, I actually like the untrimmed wild look, but I am wondering what kind of yew could this be, how tall it can eventually become, and whats the best way to prune it.
The most common type of yews grown here in Southern Ontario are either Hick’s Yews or Hill’s Yews.
Hick’s Yews, Taxus x media ‘Hicksii’, form tall columnar bush with a broad base and narrowing at the top with upright branches. It has the darkest and glossiest green foliage and bright red berries in the fall. It creates an excellent vertical accent point or can be planted to form a hedge. It grows to 2m (6.5 feet) in height in full sun or shade and will tolerate northern exposures.
Taxus x media ‘Hilli’, Hill’s Yew has excellent uniformity and dark green foliage. It’s upright form is dense, compact and the shape is broadly conical. It is slow growing but can reach 10 feet with little pruning over about a decade. Again, this is a great plant for sun, shade and northern exposures.
I have included this wonderful article from the Royal Horticultural Society in the U.K. on pruning and shaping Yew trees & hedges.