"It just died."
Did you have shrubs that failed to establish last year? You are not alone. We had a particularly challenging year for establishment, with unusual weather patterns that included twice the region's average number of days with temps in the 90's, and dramatic, all-time record-breaking heat in October.
In fact, during that late season "flash drought" even many already well-established plants became stressed or died. I have worked with 7 clients so far in 2020, some of them very skilled gardeners already, and at least half of them have shown me shrubs that failed to establish last year! This is an unusually high number of dead shrubs!
I myself lost two (non-native) cherry laurels that were planted here by previous owners of my current home; those shrubs had to have been there for at least 6 years with no signs of disease (I checked regularly, looking for an excuse to replace them with something native...well, now I guess I don't need an excuse.)
As gardeners, with the new weather patterns (if they can be called patterns at all!), I think we are going to have to become more vigilant, more observant, and more resilient.
More vigilant: A rain gauge helps build awareness of how much water your landscape is really receiving. Watch the weather temperatures. Be willing to get out the hose or set up drip irrigation (best not to use sprinklers that soak the leaves—you want to water the ground instead.) Be thoughtful about your planting schedule—we aren't going to be able to squeeze in a planting and then leave for a long trip without putting someone we trust in charge of monitoring those new plants.
More observant: Can we talk about this a minute? When I ask about how a shrub died, sometimes I hear "It just died." Come on, we can certainly do better than this! (More on this below.)
More resilient: I think we are going to have to be willing reach into our pockets and buy replacement plants. The more extreme weather patterns are going to make it necessary. Keep in mind that once a group of trees or shrubs are established, they should actually help improve and moderate the microclimate where they stand, at least in some small measure.
But if they fail to establish, big question is whether to replace with the same thing, or try something different next time. The answer to that question depends on understanding why the plant died.
[About zones: Several years ago when the new, hotter zone maps came out, we talked about shifting the zone requirements for our plant selections. But if you are already using native plants, the vast majority of our Maryland natives overlap with areas further south, and already include zone 8 or 9.]
"It just died." There are lots of different ways that shrubs can give up the ghost. If you pay attention, you might get some clues. You can then intervene with the right kind of help, or at least understand a little better what happened so that you don't repeat it. Here are some questions or distinctions to keep in mind:
Are the leaves wilting? If so, which leaves? All over the plant, just at the top of the plant, or only along one group of branches?
Are the leaves changing color? What color? Is it browning, or is it early fall color? And again, which leaves?
What is happening along the stems? If your shrub is suffering from scale, you may find funny bumps (white, or brown, fuzzy, bumpy, or smooth, depending on the type of scale). Shrubs can tolerate a certain amount of scale, but if there's a lot of them, they can overwhelm, especially a newly transplanted shrub that is under stress. Bot canker in shrubs is very common particularly when the shrub is stressed: you will see green-brown-grey discoloration along the middle of a stem, and usually the stem appears to be dying from the tip back inward, toward the base of the plant.
What is happening at the ground? Is there evidence of rodent damage? Has something been disturbing the soil? And while you're down there, how wet or dry is the soil?
What's been happening with the weather/your watering? Kind of obvious, but important for understanding whether the shrub died from too much or too little water, since the symptoms of both situations can look the same: gradual browning of the leaves all over the plant. If we had a drought and you watered a LOT (how often did that hose get left on by mistake...?), you may have overwatered. Roots need water but they also need periods of oxygen, which they cannot get in saturated soil.
Armed with this level of detailed information about the symptoms, you can go online and get much better quality diagnosis. University extension agencies often provide excellent websites with good photos. University of Connecticut has specific information in its shrub and trees database about what kind of diseases certain shrubs are susceptible to, so if you don't think it was just drought, you can look up the shrub and see what else to investigate.
At the very least, you'll have something to say that sounds soooo much better than, "It just died." :-)
Happy investigating!
Chris