Are you seeing a catastrophic die-off of an important part of your landscape? Callers to our EMG helpline often report that an extensive hedge or a mass planting is looking poorly and some of the individual plants are already dead. Losing one plant is sad. Losing many can cause big problems.
A common example concerns Leyland cypress planted as a screen. Leylands are inexpensive, pretty, and grow quickly. Unfortunately, they are susceptible to many diseases and insects, especially when grown close together. Some problems cause unsightly damage that must be pruned out; others can only be controlled by removing diseased plants. Not surprisingly, Extension no longer recommends planting Leylands:
https://www.ces.ncsu.edu/depts/ent/notes/O&T/specificplants/note133a/note133a.html
Other popular landscape choices are also at risk. With the spread of new diseases, such as Rose Rosette, Impatiens downy mildew and Boxwood blight, as well as the appearance of new pests such the Emerald Ash Borer, gardeners face an ever-changing list of potential threats to specific plants in their gardens.
This cautionary tale has a happier ending: Diverse plantings are a wiser gardening choice. Our mountain plant communities include an amazing number of species, so a variety of plants will always look more natural. Yes, each of those different plants will be vulnerable to different diseases and will attract different pests, but they will also attract more birds and beneficial insects that will help maintain a healthy balance, minimizing the need for pesticides.
If you lose your Leyland screen, plant a beautiful new hedge using shrubs of various shapes, colors and sizes. Put your roses in more than one spot in your garden; consider a mix of shade-loving annuals rather than a large bed of Impatiens. Reconsider adding boxwoods or ash trees. Your diverse landscape will limit pests and diseases to susceptible plants. You can replace those one or two plants, while still maintaining an attractive garden.