The Complete Guide to Boxwood Shrubs
Picking the Perfect Boxwood Shrub
Most plant problems come from putting the wrong variety in the wrong place. Use these guidelines to help you find the right place to plant your boxwood.
Choose the right variety to fit your space. Depending on the variety, boxwoods can vary in height from one foot to over 5 feet. If planting in front of a low window or creating a border for your flower bed, you might want to choose Dwarf English Boxwood (Buxus sempervirens var. suffruticosa) or Green Velvet Boxwood (Buxus sinica var. insularis). If you are looking for a tall screening hedge, American Boxwood (Buxus sempervirens) will grow the largest. Wintergreen Boxwood (Buxus microphylla) is a nice mid-sized choice for flanking an entryway.
Shrub expert Dr. Michael Dirr has described boxwoods as having "superb deer resistance." Try them where you've had trouble with browsing.
How to plant your boxwood shrub
Boxwoods have the potential to be very long-lived shrubs. If the right selection is put into the right growing environment (see above), they are generally trouble-free, low-care plants. Following some simple planting guidelines can help ensure your boxwoods live a long, happy and beautiful life.
Boxwoods (Buxus spp.) grow best in loose, well-drained soils that are rich in organic matter. If you are planting in less-than-ideal soil (such as the compacted "builder fill dirt" that surrounds many foundations), work in some compost or other soil amendments around where you plan to plant your boxwoods. This will help the soil around your boxwoods retain the right amount of moisture (they hate to be dry!) but also drain well (they also hate waterlogged soil!).
After planting, mulch the area to help conserve moisture around their shallow roots. Once they've been planted, try not to disturb them with digging or tilling too close-by.
Boxwood can be damaged or take on a bronze color in winter if it is exposed to drying winds. Site them where they have some protection from cold winter winds. Green Velvet is one of the most cold-hardy varieties, with excellent green winter color and the ability to survive into Zone 4.
Boxwoods like their nutrients to be released slowly. You can either work in a slow-release fertilizer at planting time or top-dress after planting. Milorganite and cottonseed meal are two good options.
Boxwoods tolerate a wide range of light conditions, from full sun to shade (although partial shade is best in hot, dry or windy areas). Take advantage of their adaptability and use them throughout your garden!
Pruning Your Boxwoods
Boxwood's tidy appearance and ease of pruning makes it a classic choice for edging planting beds, training into hedges, using in formal gardens, and even shaping into topiary.
Do any needed pruning or shaping in the spring, followed by a light shearing in the summer. Thanks to boxwood's slow growth rate, this should be plenty to keep your boxwood shrubs looking trim. Don't prune in fall to avoid excessive frost damage of tender new growth.
If you are pruning your boxwoods into a hedge, trim them so they are slightly wider at the base than at the top (they should form a trapezoid instead of a rectangle). If you keep them too straight up and down, the base will be too shaded and die out.
If your boxwoods are getting so dense that they are dying out in the center, thin them out by pruning some of the branches back in the spring by about 3 to 6 inches. Don't overdo this; it can be done over the course of a year or two to make the change more gradual.
You can also do heavier pruning if you are training your boxwoods into topiary. Pyramids and spirals are two popular shapes. However, be aware of the time commitment that this style of formal pruning requires. Since boxwoods naturally have a tidy growth habit, you may just want to work with their natural shape. To shape into topiary, try using string or wire to plan and guide your cuts.
Boxwoods can be affected by leaf miners. This insect causes whitish or transparent trails in the leaf, caused by larva burrowing into the leaf. Since the problem is mostly cosmetic except in extreme cases, you can simply remove the most affected leaves with spot-pruning (a damaged leaf will not "get better"). To help stop leaf miner damage from occurring, you need to stop the adults from laying eggs on the leaves in the first place. Spray insecticidal soap or horticultural oil on your boxwoods in the spring, making three applications one week apart. If leaf miner continues to be a problem, try a commercially-available pest control product labeled for leaf miner control. Always read and follow label directions when using pesticides. If you have been troubled by this pest, you may want to choose Dwarf English Boxwood, which is considered the least susceptible.