Posted 12 February 2008 - 05:33 PM
I agree with , there are many different varieties each with their own unique growth habit and look. A lot depends on what you are trying to achieve. For example, "Winter Gem' has a larger darker, glossy leaf than 'Green Velvet', which has a smaller, more oval matte texture to the leaf. If you are combining or using the Boxwood as a back drop or with other evergreen plants, it may make a difference in how all the textures and shades of green play out. I have also found 'Winter Gem' to be a little more on the woody side than 'Green Velvet' and better if you want a 2-3 foot hedge, rather than one smaller. I am trying 'Green Gem' in my white garden at Cranbrook because I wanted a slow growing boxwood that grows more naturally into a 2' ball shape. I am putting them in a semi-circle, with space between, keeping it geometric, but without the filled in hedge look. It's an experiment in design...ask me in 2 years how it looks. And some designers like 'Green Mountain' for it's pyramidal oval shape.
As for hardiness, buy from a local grower if that is a big concern. I have bought most of my boxwood from Auburn Oaks nursery since they have a farm in Fenton where they grow most of their boxwood and other shrubs. It's a small nursery, but great on service. You can purchase at wholesale rates as well.
For pruning, I prune both in April and August to keep and maintain size and as well as to keep that clean look going into the winter months.
Hope that helps!