I've seen it too, and can't remember the name. I recommend that you post this in the Name That Plant forum here on Gardenweb, and you will get an answer right away.

@agardenstateof_mind would know. Or, you can also contact your county's Master Gardeners, NJ Master Gardener Helplines

:-) I'm stumped, too; though it does look familiar. My first thought was physocarpus (ninebark) 'Diablo", but, no, ninebark leaves are slightly 3-lobed. Similar to copper beech or purple leaf plum, but the leaves appear more distinctly textured than either of those.

There's an app for leaf ID, though I've not downloaded or tried it yet. MG Helpline as a good recommendation ... and most of them accept emails, so you could email the photo.

I hope you'll report back when you get an answer!

How about a purple-leaved variety of hazel?

Corylus maxima 'Purpurea' - purple leaved filbert - just might be it! Thank you, Atlamol. Habit, according to one website: "A very small upright tree or large shrub producing purple-tinged catkins
in late winter, followed by deep purple, heart-shaped foliage in summer
with curious and striking purple tinged fruit husks in late summer
which ripen to edible hazelnuts by autumn." According to another, leaves may fade to purplish-green during summer. May reach 15-20' at maturity.