Diable Ninebark Patio Tree features white flower clusters in June. The trunk of the tree has dramatic tan, brown and dark brown, exfoliating bark. This feature provides all season interest, especially in winter. The body of this small tree is vase shaped. Physocarpus opulifulius 'Monlo' or 'Diabolo' foliage is dark maroon and almost black with a metallic sheen that can be seen in bright sun.