Boxwood issue

Question: I moved into a house with boxwoods. They have been improperly planted (too high on the slope down and landscape fabric over root ball). They have been having issues all year with leaf drop and due to back.  Spider mites were treated with neem oil and the plants seem to be growing in but there is still leaf discoloration and curling on new growth. I do not see any stem discoloration. 

I think they would benefit from being replanted but I was hoping to get the disease under control first to reduce stress. I don’t think this is blight, but would I be better off buying new plants or trying to rehab these?

responder: The Question Asker Replied August 04, 2024, 2:51 PM EDT
response: I wanted to add these pictures and note that I don’t see any visible pests after the neem treatments earlier in the summer. The leaves also largely stay on the branches if they turn brown.

responder: The Question Asker Replied August 04, 2024, 2:58 PM EDT
response: I wanted to add these pictures and note that I don’t see any visible pests after the neem treatments earlier in the summer. The leaves also largely stay on the branches if they turn brown.

responder: Thank you for contacting us!  Replied August 06, 2024, 10:56 AM EDT
response: Thank you for contacting Ask Extension. After looking at the pictures that you sent, it seems like the boxwoods have Macrophoma Leaf Spot. The most obvious symptoms are the many tiny black raised fruiting bodies found on dying or dead straw-colored leaves. Also, the red-brown lesions on the leaves that are still green indicate that too. Pruning infected branches is sufficient management for this fungus. Also, thinning pruning is recommended to increase air circulation to help to reduce moisture. I have included a publication on how to prune boxwoods. Also from your pictures, it does not appear that the planting height is an issue. But you should move the mulch back from the plant stem by about 3-4 inches. And the landscape fabric (I believe that is what the material sticking up from the mulch) should be removed. This can cause girdling in the shrubs and excess moisture to be held in the soil.  Here are some publications for your reference: https://extension.umd.edu/resource/pruning-shrubs-and-hedges-home-garden/ https://extension.umd.edu/resource/boxwood-identify-and-manage-common-problems/ https://extension.psu.edu/boxwood-diseases https://www.canr.msu.edu/news/browning-of-boxwood-is-it-boxwood-blight Please contact us if needed for more help.

responder: Thank you for contacting us!  Replied August 06, 2024, 10:56 AM EDT
response: Thank you for contacting Ask Extension. After looking at the pictures that you sent, it seems like the boxwoods have Macrophoma Leaf Spot. The most obvious symptoms are the many tiny black raised fruiting bodies found on dying or dead straw-colored leaves. Also, the red-brown lesions on the leaves that are still green indicate that too. Pruning infected branches is sufficient management for this fungus. Also, thinning pruning is recommended to increase air circulation to help to reduce moisture. I have included a publication on how to prune boxwoods. Also from your pictures, it does not appear that the planting height is an issue. But you should move the mulch back from the plant stem by about 3-4 inches. And the landscape fabric (I believe that is what the material sticking up from the mulch) should be removed. This can cause girdling in the shrubs and excess moisture to be held in the soil.  Here are some publications for your reference: https://extension.umd.edu/resource/pruning-shrubs-and-hedges-home-garden/ https://extension.umd.edu/resource/boxwood-identify-and-manage-common-problems/ https://extension.psu.edu/boxwood-diseases https://www.canr.msu.edu/news/browning-of-boxwood-is-it-boxwood-blight Please contact us if needed for more help.