Drought tolerant plants or at least those that will survive with minimal water are always in demand, particularly in the mid west of the country. Drier conditions due to lack of rainfall combined with ever present winds set up a condition that is not favourable to many plants. The Ninebarks are tolerant and well suited to conditions as described and luckily, they come in a considerable array of colours. One can suppose that the odd common name relates to the habit of these plants to have rather shaggy, peeling bark, perhaps into nine layers? Botanically they are labelled as Physocarpus opulifolius with derivatives for cultivars and varieties, but generally all called simply Ninebarks. I have several varieties in my urban landscape and yes, each year about this time, they require some pruning, renewal and often times a thinning. ‘Diablo’ has been one of my favourites for many years with its rich, deep reddish-purple foliage contrasting beautifully with any of the chartreuse or yellowish companion foliage. Her flower buds are a rather showy pink then burst into white clusters at the ends of each branch. The foliage is somewhat coarse, but it provides a marvelous backdrop for the early spring flowers. My plants remain in bloom, of course depending on the winds, for about three weeks then the magic of texture and foliage takes over. Often, the plants will set fruit, but I wouldn’t suggest them as a food source as they are toxic in large or uncontrolled dosages. In times past, the fruit of the native Ninebark was used in traditional medicines as a laxative as well as for many female associated problems and infertility. In the fall my ‘Diablo’ turns a rather orangey-red and with hard frosts even more red. Once all the foliage has been lost the shaggy bark of this variety as well as the others, adds interest to the winter landscape. The older specimens reach about 2.5 metres in height and would probably go further if I neglected them. Consider this growth habit when you are establishing location as without care they can be rather tall and thicket-like.
There are many varieties of Ninebark that do not exceed reasonable limits for the urban garden, and of note all Ninebarks are extremely tolerant of urban climate situations, pollution, compacted soil and all the other delightful conditions that the city offers. This is, naturally one of the reasons that you will see so many varieties of ninebarks used in mall landscapes and city streetscapes. For the novice gardener, this is great news as any plant that can withstand this abuse should do very well with some TLC. The specimens that provide the best colour and show in my urban garden receive the most sun. Others that are less fortunate still perform very well however with lighter foliage shades. ‘Little Devil’ Ninebark is the dwarf form of ‘Diablo’ reaching only 1- 1.5 metres in height. This ‘lil rascal will provide the same intense foliage colour of it’s cousin as well as white-pink clusters of flowers this month. ‘Summer Wine’ is heralded as a dwarf also however tends to stretch a tad more than most of the literature cited. She boasts a very dense and compact growth form, with the odd ‘spidery’ stem running above the others. Her flowers are also June borne and range from white to pink, contrasting beautifully against the deep reddish foliage. ‘Centre Glow’ companions very well with both, however should be planted in the background as it will reach 2 metres if unchecked. The foliage of ‘Centre Glow’ does just that… the new growth glows with a yellowish tint contrasting against the red of the older foliage and outer edge of each leaf. I have used stalks of this and other Ninebarks in floral arrangements for the patio and deck. The flowers don’t last very well but the striking foliage makes up for it indeed.
There are many varieties to ogle over all with similar cultural requirements. Consider including ‘Dart’s Gold’, Nugget’, ‘Amber Jubilee’ and ‘Coppertina’ in your portfolio of Physocarpus.