Deep burgundy-red buds open to dark red flowers with a black eye. Rhododendron 'Dark Lord' grows 5 to 8 feet tall and wide in part shade, hardy from Zone 5 through Zone 8.
The foliage is dark green and the whole plant reads moody rather than bright, which makes it useful for contrast against pale flowers or variegated foliage.
The large-leaf rhododendrons hold their foliage year-round rather than thinning like the small-leaved types. Below about 25 degrees the leaves droop and curl up, curling tighter the colder it gets, and they open again within hours once temperatures rise. It looks alarming the first winter and it is entirely normal, a water-conserving response rather than a sign of trouble.
This gets large, up to eight feet in both directions, so give it room. Acidic soil is necessary, roughly pH 4.5 to 6.0, with good drainage and steady moisture. Mulch the shallow roots.