The elongated leaves suggest a paniculata but there are many cultivars that produce dark stems and-or cultivars with lacy blooms (Brussels Lace, etc.) although the ones in the picture a quite lacy and not dense looking yet. The care of paniculatas is the same though: maintain 3-4" of mulch; maintain the soil as evenly moist as you can during the summer; can take full sun in the summer but give some 3-5pm shade in hostile summers like those in Texas and such; develops flower buds starting around late spring or in the summer and these then open right a way; some varieties with large, heavy, dense blooms can flop a lot so try not to prune them too much if pruning is necessary. Deadheading can be done at any time although I would avoid the time when they are developing flower buds or when they are blooming. Less sun can make the color changes occur more slowly than if exposed to full sun. Usually, they are quite winter hardy to z3.