We can't tell from your photo alone what might be causing your shrub such distress (and maybe death).
When were these shrubs planted, and did they look healthy when they went in the ground?

If they are new, difficulties are usually related to problems with planting, site conditions, accidental herbicide use over the roots, or aftercare. 
You can look through our shrub planting page for clues: https://extension.umd.edu/resource/planting-tree-or-shrub/
Planting too deeply is a common stressor, but it wouldn't kill quickly if the plants had only been planted last season.
When did you start to notice symptoms and what did they look like?
During the first 18 to 24 months in the ground watering when needed is crucial. Last year central Maryland had serious and prolonged drought conditions. 
These plants like a moist soil and planted in full sun would be quick to dry out. Here is our watering information: 
https://extension.umd.edu/resource/watering-trees-and-shrubs/
Tug upwards on the plant to rule out chewing damage from voles, which can happen just underground and sever the shrub from its roots.
Any weed chemicals applied nearby?

Did it leaf out at all this year? 
It is hopeful that the branches are flexible-  if the problem is remedied and the roots are healthy enough they might be able to recover, including sending up new growth from the base.


Christine

Hey there, Christine.

Thank you so much for your swift response.  So the soil I planted it in has a bit of clay in it and seemed to retain water fairly well.  I'd water it regularly, each day in the beginning, making sure to soak just under it and the surrounding area.  This is the first season it's been planted.  I carved out the depth of the root ball, loosened the roots, loosened the soil about double the size of the rootball.  One developed some leaves but then they started to wilt away from what I could see recently.  Just noticed this a few weeks ago, fathomed it might be the watering and tried to increase the moisture but that didn't seem to help.  I'll pull up the bushes and check the root system but, as far as I'm aware, there's been no issues with pesticides or herbicides outside.

It sounds like you are doing everything right.
When did you plant?
I've not worked with that particular variety but I would expect that the stems would have some color.
 Were the plants dormant or fully leaved when you planted them? Did the leaves show any symptoms before they died?
Do you trust the nursery where you got them and do you have a warranty for replacement?


Christine

Thank you for the additional information. In my assessment, the shrub(s) pictured look dead and probably need replacement. It can be hard to tell what the original issue was, but one common infection that shrubby dogwoods are vulnerable to is Botryosphaeria canker. Although the linked page currently focuses on Rhododendron, a variety of shrub and tree species can contract that disease in the right conditions. If the shrubs happened to be drought-stressed (perhaps not by your care, but prior to that) or some other event made them more vulnerable to infection, an asymptomatic canker infection might have been present but hadn't yet caused branch dieback by the time you purchased or planted the shrubs.

Another possibility is root rot, though in general, shrubby dogwoods are more tolerant of damp soils than their tree cousins. (This tolerance can vary from one species to another, though...several species, both native and non-native, can be grown in Maryland, but they don't do equally well in wet or poorly-drained sites.) It sounds like the shrubs were being watered often, though it's hard to say if that had an impact on dieback. For the future, we recommend feeling the soil first, about five or six inches down into the root zone. If it's becoming somewhat dry to the touch at that depth, a thorough watering may be needed. If damp when checked, watering can wait. (Foliage can wilt for both over-watering and under-watering, so by itself is not a very reliable indicator of the need to water.) Over-watered roots tend to get readily infected with "root rot" pathogens and do not recover. (There is no fungicide to cure them.) In comparison, if Botryosphaeria canker killed the branches, the roots might still be okay and eventually able to produce replacement branches (called suckers).

If you uproot a plant to check roots, see if any look darker, mushy, and pull apart easily. Roots dead from root rot tend to pull apart with little force, separating into an outer layer that tends to be mushy/soft and an inner stringy core. In comparison, roots dead from other causes (or still alive) will take more force to break and tend to snap cleanly in two instead of splitting into those layers. The dead branches won't necessarily be brittle enough to break easily at this point, so if they remain pliable, that doesn't necessarily bode well for their recovery, especially since they are not currently the color of healthy wood.

Even if canker only killed branches, though, it still may be worth returning the plants for an exchange/refund, if you are able. The nursery would not necessarily have been able to detect an infection if the plants looked normal at the time of sale, and unfortunately it's not uncommon for plants to manifest symptoms of an infection a while (days, weeks, or even longer) after the infection actually took place, complicating a diagnosis.

Miri