The ninebarks are popular shrubs.
The ninebarks, Physocarpus opulifolius, are popular shrubs. For some time the golden ninebark was the standard, but the Diabolo is now seen in almost every garden. Less hardy than the gold varieties, it can also send up very long 1 - 1.5 metre shoots.
P. opulifolius, the common ninebark, is the larger shrub, two to three metres in size. When pruned to be somewhat open, the effect works well, makes a beautiful "little tree".
P. opulifolius 'Darts Gold', is the smaller of the golds, usually growing to about 1.5 metres.
P. opulifolius 'Diabolo', or purple ninebark, is a narrower form, more upright, not as hardy as the other two.