It looks like weed killer damage, to me. It might be from someone spraying nearby with imperfect care, or wind. Or it might be from animal manure from fields treated with long lasting herbicides.

thanks - Tugbrethil. I can't imagine how that might have occurred!

If they are near the property line, the neighbor might have sprayed something. If you used a commercially prepared "composted manure" as a soil conditioner, that could have contained a long-lasting herbicide that may be affecting the growth. If in containers, the growing medium might contain similar manure--not my idea of a good medium--or it might contain composted clippings from a similarly treated lawn.