I've been very pleased so far with two plants of the Buxus variety called 'Rochester' which have sailed right through two very serious Maine winters. I've got them flanking my front steps, so they tend to get buried and re-buried in snow as the porch and sidewalk are shoveled and the weight of the double layer of snow bears down on them. In spring they bounce right back, regain their former shape, and put out vigorous new dark-green leaves -- just like the catalog promised they would. Now, in their third summer, I'm trying to decide whether or not to prune them. (They are still only about 15 inches tall.) My reasons for not wanting to prune them are: • I'd like them to get tall enough to hold their heads, so to speak, up above the snow level, since the whole point of evergreens is to have something green to look at in winter. • Thus far, their natural shapes are appealing, and rather in keeping with the informal character of the plantings around them and with the "cottagey" style of the house itself and its woodland setting. Are there compelling reasons, though, why I ought to prune these shrubs? Would it, for example, encourage fuller or sturdier growth, or prevent them from getting leggy over time? I anticipate that I will want to prune them at some point, to maintain a certain degree of shapeliness. But I wonder how long I can safely put this off. Thanks for any thoughts.
Shearing box into geometric crisp shapes is done primarily to convert the shrubs into architectural elements. If you like the way they look without shearing, there is no reason to do so. Cutting out individual shoots that have broken in snow, blighted off or grown beyond the desired shrub size or outline are examples of selective pruning. This is different from shearing the whole plant into an unnatural form, which is non-selective pruning.
additional to ron's observation: crisp geometric shapes as an architectural element are usually for more formal settings. i prefer to leave bushes (boxwood, azalea, etc) in their natural (informal) form and do selective pruning and only when absolutely necessary. i find the unaltered growth form a much more appealing architectural element - especially on my own property - it's very small, so formality doesn't really 'fit'. free-flowing works better and is just more my 'style' :) there's a place for formal and a place for informal - and sometimes, the two can be integrated in one location with much success (and sometimes integration can fail miserably, lol). many things factor in as to what is more appropriate to do. first, personal preference. second, location (general area). third, style of the house. fourth, size of property. fifth, other existing plantings. if you like the growth pattern that's developing, then leave it as is and just tweak things as needed. if this form fits with the other plantings, then i wouldn't think going with a straight-sided form would enhance the area. how large are they now?? they can, eventually get leggy - that can occur from never doing any pruning at all as well as repeatedly doing too severe pruning on the lower parts.
Here's a nice mature Box, never trimmed. They get to look very graceful. This one's about 6 or 7 metres tall. I suspect though you might have difficulty getting a box to survive above the winter snow line in zone 5 - it'd probably get frozen back to the snow level.
Thanks for this helpful discussion. You're right, Ron -- the only vendor I see calling the plant simply 'Rochester' is the one I bought it from, Bluestone Perennials. Michael, that's an amazing photo. The only large mature boxwoods I have (knowingly) seen in North America were at the Washington Cathedral in D.C. -- needless to say, an Anglican institution. These were tiny-leaved plants that had grown into great wizened specimens perhaps 9-10 feet tall; I speculate they dated back to the original planting of the Bishop's Garden in (I believe) the 1920s. But they were chopped nearly to the ground several years ago and were struggling to regenerate the last time I visited. I share your concern over hardiness. 'Pride of Rochester' is one of several boxwoods bred in recent years -- mostly in Canada, I think -- that are claimed to be hardy to zone 5 or even to zone 4. I've tried one other, 'Vardar Valley,' which also comes through winter unscathed, though it has a more stiff, upright form, its leaves are a kind of dusty green, and it seems more susceptible to snow damage. Others are 'Green Mountain,' 'Green Velvet,' and 'Winter Gem.' One (wholly subjective) thing I've observed about winter hardiness since moving to Maine -- 21 winters ago -- is that more often than not, plants of doubtful hardiness show some kind of winter damage no matter how heavily they are protected by snow or by deliberate measures taken by the gardener. There will be scorched leaves or dead branch tips or a general loss of vigor ... something. And this has been the case with some other boxwoods I've tried to grow. So I'm hopeful that 'Vardar Valley' and 'Pride of Rochester' will continue to perform as advertised. And no pruning for now!
It all depends on which boxwood. We have 4 Buxus sempervirens 'Suffruticosa' planted in Oct 85 that have never been pruned or even trimmed. They are lovely 2 ft tall dense ball shaped plants that look like they have been sheered. Ray
When I was training as an arborist in Southern England in the mid-nineties we were taken to Box Hill in Surrey to look at the amazing box (regionally native Buxus sempervirens) woodlands on the dry chalk slopes there. They looked gnarled, tortuous and full of character and it was like being a giant walking though an ancient forest (which is what it is, albeit a very low one). There's a lot to be said for letting woody plants alone to reveal their "natural" character. Although, in the case of box, it may take a while.. Keeping the soil relatively free-draining seems to be the key to avoiding the legginess they're sometime prone to when treated too well (lots of water and rich mulch) in gardens.