While flashier but typically weaker modern cultivars of so many other specie are being developed, the most popular of the many cultivars of English boxwood, Buxus sempervirens, remain the same. There is not much to improve on. Most cultivars get only a few feet tall, and are densely foliated with inchlong evergreen leaves that are excellent for topiary and low formally shorn hedges.
One of the difficulties with formal hedges, or any formal application, is replacement of any specimens that die. There are not very many of the different cultivars available locally; but it can be quite difficult to distinguish between some of them. One specimen of the wrong cultivar ruins conformity! Another concern is that the aroma of the foliage when disturbed may be objectionable to some.
In the wild, English boxwood grows as small trees or rather larger shrubs with relatively open structure. Locally, such specimens are only very rarely found in old Victorian landscapes, such as at the Winchester House. 'Suffruticosa' is so compact that it popularly allowed to grow as as unshorn and nearly spherical shrubs. 'Argenteo-Variegata,' 'Variegata' and 'Marginata' are variegated. -- Tony Tomeo