I'm in North central Iowa with several 17 year old burning bushes with the same problems. They were fine in 2018. I have no idea whats going on. The shrubs have suckers at the soil line. I see no rabbit, vole or critter damage to the bark. I had wire 3 feet high around the base over the winter to keep the rabbits out on the 2 that seem to be "d-e-d" dead. Even with some rabbit damage ... they have always leafed out. We have a lot of anthracnose this Spring on the Ash trees. Which happens when the Spring is very wet (like this year) But that has never seemed to affect my Euonymus.

we had one on the driveway ... scratching the car.. and the gutters ... dad had me cut the six inch trunk 4 inch tall stump .. and with no insult to the root mass ... it was back to the gutter in a year or two .... so the only question might be... was it a root issue.. or a winter issue ...

but whats to lose.. if you cut it all the way back .. and it dies.. what gal said ... lol ...

ken

ps: timing was not important ... because he had a hate on for it... besides.. do you want to look at that half dead thing every time you see it???

Here's a photo of my shrubs. I've seen similar damage to BB shrubs around my small North central Iowa town. The BB on the left just got a couple of green leaves several days ago. The shrub on the right is only 33% leafed out. I'm just gonna be patient and leave them alone this summer. There is growth at the soil line which I normally would clip, but I'll let it go this year. I can always cut them down in September. Consensus of the "great minds" at the local coffee shop think it's a winter issue. We had a couple of warm days in late winter which may have "tricked" the bushes to think it was Spring. Then winter came back with some really cold polar vortex weather. One old curmudgeon called it "Fake Spring"

Same issue here also in northern Illinois. Mine were 23 or so years old. I was sick of looking at them with only 1/8 of branches having leaves, so I took the saw to them today. Now I get to go find their pretty replacements.

I find I have die back on mine some winters quite severely in 4B. I thought I had read that they were shallow rooted, but now I can`t find evidence of that.