Is it on the border of your property Konrad, it looks like chemical spray drifted on to it. Have not seen that on any trees that I can remember.

konrad...somewhat unrelated...do your honey bees work all your linden trees? If so, what is the honey like? And do the bees prefer it to legumes and canola?

Might just be in the genetic make up of the tree to produce this unusual cupped foliage

Thank you all!
Wayne, no, its in the middle of the nursery,...been getting this same thing for several years now. Or, I look at it more closely.

rosecavalier
That's the idea,..trees still too small for honey bees to be interest in,.. at least another 5 or 10 years away,... they focus on the large crop, right now it's clover, ..I'm too far away for Canola fields,..thanks god.

Blossoms fully open now,..mostly wasp and bumbles feasting on it, only seen ONE honeybee, rather disappointing,..smells soooo...nice!