Unfortunately, no, we do not expect watering to salvage the plant at this point; too much dieback has already occurred. It's hard to tell with symptoms this advanced what the original cause was. Boxwoods can be vulnerable to several stressors (refer to the linked page), but not every variety has equal susceptibility to each issue. If this planting bed is in full summer sun, the heat buildup from the wall not far behind the plants might be a contributing factor, especially if they had not yet been watered up to this point during this year (and last year's) droughts. If you replant, monitor the new plants closely for watering needs, though boxwood can get stressed by a full sun location (despite how often they are grown in such sites) and another species might be better-suited to that location if it tends to get hot and dry in summer.

Miri

Thank you Miri.  This is a western facing location with lots of full sun.  What other species would you recommend?

We can share some ideas, but a bit more information about the site first would help us to narrow-down some options. Does the soil drain well, or tend to stay soggy after rain, or get dry fairly quickly during dry spells? Do deer visit the yard and browse regularly? (They don't like boxwood, but will eat a lot of other plants.) About how large would you like plants to grow in this location, without relying on pruning to keep their size restrained?

Miri

Hi, the soil does stay a bit soggy as the overhang from the roof (2 story home)  is about 6 inches or so behind the current row of boxwoods.  It does dry quickly most of the time due to the western exposure.  Deer are not a problem.  Two feet or 2.5'  max height (without pruning) would be ideal as the location is beneath a set of three windows.

Thank you for the additional information. Below are some ideas, though it's not an exhaustive list. If you don't need/want the plants to be evergreen, we'll include some deciduous options as well. Some of the candidates below will need to be dwarf varieties/cultivars, since the full-size version will be much too large. Dwarf simply means they grow more slowly and mature comparatively smaller as well, though plants never truly stop growing, so take plant catalog or sign information about size with a grain of salt. They do slow down with age, though, so stated sizes won't be egregiously wrong, just not a final height that the plant would never exceed.

Needled evergreens (conifers) in general are not capable of replacing lost foliage on older wood, which means that while light pruning now and then is fine, heavier, size-reducing pruning will not be something they tolerate well. Therefore, you could expect to keep a dwarf conifer maturing in the 3 or perhaps 4-foot range sized to fit this space, but not one that would mature to, say, 6 feet tall. "Miniature" conifers grow even more slowly, so should never need pruning to fit into most spaces, but the trade-off is that they also may take a decade or more to get any size to them, since to qualify as miniature, conifers would be growing only about an inch per year. ("Dwarf" is technically anywhere in the range of 1 to 6 inches per year.)

Broadleaf (non-needled) evergreens can be trimmed, though it's still best to avoid having to do so heavily by choosing a variety that stays naturally very compact. Both evergreen types are included in the list below.

Evergreen:

• Japanese Cedar (Cryptomeria japonica) -- specifically a dwarf or miniature cultivar, since the regular form grows much too tall; dwarf cultivar examples include 'Birodo', 'Compressa', 'Dragon Prince', 'Dragon Warrior', 'Golden Promise', 'Little Diamond', 'Pygmaea', 'Tenzan', 'Twinkle Toes', and 'Vilmoriniana'
  • some varieties "bronze" in winter, meaning that they develop a dark chocolate- or caramel-toned blush to the foliage in winter, greening-up again in spring, and a few have a golden-yellow color on the youngest growth
• Japanese Plum Yew (Cephalotaxus harringtonia)
  • grows wider than tall, but more compact varieties height-wise include 'Duke Gardens', 'Fritz Huber', 'Gold Dragon', 'Prostrata', and 'Hedgehog'
• Juniper (Juniperus, several species) -- as long as the soil drains well, even when occasionally damp
  • Juniperus squamata cultivar 'Blue Star' is mounding and blue-green (more blue-gray in winter), and cultivar 'Holger' is blue-green with creamy yellow tips to the new growth
  • Juniperus virginiana cultivar 'Grey Guardian' is wider than tall and silvery blue-green; species is native
• False Holly (Osmanthus heterophyllus) -- cultivar 'Kaori Hime' (also known as 'Party Princess') stays short enough and has very tiny leaves; fragrant autumn flowers
• Cherrylaurel (Prunus laurocerasus) -- only cultivar 'Mount Vernon' stays short enough, and will grow wider than tall
• several kinds of holly (Ilex) -- it would be best to verify this soil is acidic enough before selecting holly, as they thrive in acid soils and can struggle when stressed (like being too wet) and soils are too alkaline, as it can sometimes be next to a foundation
  • Japanese Holly (Ilex crenata) -- most grow too tall, and nearly all will grow wider than tall as well, but cultivars 'Hoogendorn', 'Golden Helleri', 'Kufujin', and 'Soft Touch' should fit height-wise
  • Yaupon Holly (Ilex vomitoria) -- can be harder to find than Japanese Holly; several dwarf cultivars, though 'Micron' and 'Stokes Dwarf' (also named 'Schillings') should fit best; native to the southeastern U.S., but not locally

Deciduous:

• Summersweet (Clethra alnifolia) -- dwarf cultivars include 'Hummingbird' and 'Sugartina Crystalina'; best if irrigated during drought, and may sucker (grow new stems from the root spread) if happy and damp; very fragrant flowers draw pollinators; native
• Black Chokeberry (Aronia melanocarpa) -- dwarf cultivar 'Low Scape Mound' will fit; once established, adaptable to damp soil and tolerant of drought
• Creeping Cotoneaster (Cotoneaster adpressus) -- despite the common name, this is less of a sprawling groundcover than other types of Cotoneaster; cultivar 'Tom Thumb' (also called 'Little Gem') forms a mound and stays short enough, though eventually may get wider than tall
• Glossy Abelia (Abelia x grandiflora, may be listed under Linnaea) -- listed here because it can range from mostly deciduous to mostly evergreen (the more mild the winter and wind-sheltered they are, the more likely they'll retain leaves); cultivars 'Confetti', 'Little Richard', 'Golden Anniversary', 'Kaleidoscope', 'Mardi Gras', and 'Pinky Bells' should all stay short enough

If these and others don't appeal, you can choose boxwood again, but we recommend that any you plant be varieties that are resistant to both Boxwood Leafminer and Boxwood Blight, two of the more damaging pests/diseases for boxwood; of the dozens of cultivars on the market, only a handful of the newest have above-average resistance to either/both of those issues.

Miri