Boxwoods keep dying

Question

Boxwoods keep dying from the back and then eventually fully dies…help! All others around it are fine. We put in new front landscaping and these gorgeous boxwoods. They are all doing great except two and we don’t know why. They get a tiny bit less sun than the boxwoods next to them but not so much less to kill them (or so I thought). They are closer to house…could that it? Someone said it is because they are right next to gardenia trees (something about the soil) but that can’t be right because two others are under the tree and doing fine. There is a drip watering system to each plant. Before I replace, I want to figure this out!

Answer 1

I would suggest you pull back the mulch and check the soils moisture level. Make sure the soil is draining and that you do not have a case of root rot.

I’m not sure of your growing zone, but you may be looking at winter as a possible source of the Boxwood condition.

The shrubs closest to the house may be warming during weather changes. Though they are dormant in winter, a warm up could result in them coming out of dormancy and then when weather turns cold it can kill off the subsequent new growth.
Subsequent freezes can then kill off the remainder of the plant.

You can prune back to healthy green or if the entire shrub is effected, you could prune back hard; this still could result in the loss of the plant.

Remember that the North side of a house is the best location to plant Boxwood.
Direct sunlight in both winter and summer can kill Boxwood.

Provide moist soil year round. 1 inch of water every 10 days with a soaker hose, make sure the moisture is reaching 6 to 8 inches into the topsoil.
3 to 4 inches of hardwood mulch should be applied, but keep the mulch away from the base of the plants.

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-care.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-watering-tips.htm