General: Boxwoods are actually quite adaptable if they have their basic needs met. I grow English and other boxwoods in the field, unprotected from the elements in the full sun and most do fine. However, as a general rule the plants will like it better with some shade and some protection from the winter winds and thawing. This last item refers to the phenomenon of damage to the southern side of boxwoods when the winter sun hits the plant after a heavy overnight frost.
Soils: Boxwoods like water but they like good drainage.
The Eastern Shore has very sandy soil and thus good drainage. If your soil is heavy or clayey, I would add some compost, etc., to improve the drainage.
pH: Neutral is best. We add lime to our soil and potting media.
Fertilizer: We use long acting fertilizer such as Osmocote 12 month slow release fertilizer. Friends of mine just throw some 10-10-10 around the plants every so often. The ladies of Eastern Shore suggest fertilizing around Christmas time but we usually start in February or March before the new growth gets started.
Pruning: Boxwoods can be pruned most anytime. We usually shape them up in the winter before new growth has started. Older plants appreciate some thinning by breaking off small limbs .
Mulch: I have mixed feelings about mulch. Too much can make the soil stay wet and thus encourage root rot. One way I have found for weed control is to put down ground cloth and cut holes where you want to plant the boxwoods. A thin coat of mulch can be put on top of the cloth.