Physocarpus opulifolius - Ninebark

Physocarpus opulifolius or Ninebark is a deciduous bush with a naturally graceful trailing habit and foliage that changes colour throughout the seasons. It dazzles the garden in the spring with beautiful shades of purple-red or golden yellow, and again in the autumn with a foliage that ranges from yellow to orange, red, and purple before falling. The vibrant foliage is accompanied by reddish fruits. In early summer, it produces purple buds that open into white-pink umbels of flowers. Easy to grow as a free hedge or on the edge of a garden in moist soil.

Physocarpus opulifolius belongs to the Rosaceae family and is native to the eastern United States, Quebec, and Manitoba. This bush has a medium to fast growth rate and can reach a mature size of 1.50 to 3 metres (5 to 10 feet) in all directions in its natural habitat, with a dense and bushy habit that tends to sucker. The initially upright branches arch with age, giving the bush a graceful and natural appearance. Noteworthy for its young leaves that emerge in a reddish hue, it becomes even more astonishing when they blaze in autumn. The trilobed leaves, deeply cut and serrated, measuring 5 to 8cm (2 to 3in), resemble the leaves of Viburnum opulus, hence its species name "opulifolius". After the spring reddening, they adopt a bright yellowish-green colour. They are deciduous, alternate, with well-defined veins. The spectacle of the foliage continues when the flowering occurs, from May to July. It takes the form of flat corymbs adorned with purple buds that open into small white to pink flowers, nectar-rich and highly visited by pollinating insects. They are followed by red fruits in the shape of small bladders, appreciated by birds in autumn. The bush, bare of leaves in winter, remains decorative with its exfoliating bark, ranging from beige to reddish-brown.

The visually striking Ninebark will find its place in a flower bed, creating contrasts with light or golden foliage shrubs. It will be charming as an informal hedge, alongside spireas (Spirea arguta, Spirea x billardii), viburnums, winged Euonymus (Euonymus alatus), or a Neillia affinis that it will illuminate. To accompany its changing colours, Heucherellas, for example, can be planted at its base.

The name of Physocarpus opulifolius comes from the Greek 'phusa' which means air bubble or bladder, and 'karpos' which refers to the fruit, in reference to the fruit's shape. The resemblance of its foliage to that of Viburnum opulus earned it the specific name "opulifolius". Introduced to Europe around 1687, the numerous vibrant cultivars created in recent years have led to its strong resurgence in gardens.