Gerry

thank you for contacting UNH Extension Infoline.

Boxwoods, similar to all evergreens still photosynthesis in the winter and need water. The issue you have may be due to a lack of water over the winter.

You may want to get a soil test for the area where you have re-planted if you did not do so previously, which will help to determine if any fertilizer or addendums are needed.

See attached link:

Soil Test

Remove all last year's mulch and reset with new mulch of 2" -3" Add any fertilizers , addendum over the mulch, not directly to the bush. 

Maintain a watering schedule. boxwoods need an inch of rain per week.

Hopefully, the plant will return to its true green color! As a caution do watch for any changes on the plant as disease can set in more easily when a plant is stressed.

The same applies for your ornamental plum, though it is not an evergreen and its water needs during winter would not have been as pressing. Do get the soil tested, do clear around the tree and apply new mulch and maintain a watering schedule if the weather is not co-operating.

I hope this helps.