Boxwood in winter. Don't neglect sick bushes. Protect against diseases and pests.
Boxwood that develops fungal diseases in the fall is very dangerous to leave untreated until spring. During winter, prolonged thaws with high temperatures above zero can cause the disease to progress, and by the time warmer weather returns, we'll have bushes that are beyond saving. To stop the disease from progressing, boxwood can and should be treated in winter, when weather conditions permit (long thaws without nighttime frosts, with above-zero daytime temperatures). Under these conditions, copper-containing products (copper sulfate or Bordeaux mixture) are the best choice for treating boxwood. Unlike many other fungicides, they work well at low temperatures and do not lose their effectiveness.