One of the frequently asked questions at Gardeners forums and Garden-expert panel question-times goes something along the lines of:
“How can I control/remove/eradicate a bamboo that’s taken over the entire garden/neighbourhood/northern hemisphere…”
Well, maybe I exaggerate, but only slightly. Certainly bamboos seem always to provoke strong reactions in gardeners – loved and loathed in equal measure – but, as is so often the case with gardening, it’s all about having the right plant in the right place and too often these often magnificent plants are unfairly castigated due simply to poor planting choices. After all, most gardeners wouldn’t think of planting an Oak tree in a small back garden, and then be surprised when it turns into a forest giant, and some bamboos are in much the same position: victims of poor research and lack of forethought on the part of their original planters and forever destined to be progressively dug out and continually cursed.
But, as I often seem to find myself writing in these blogs, it doesn’t have to be that way. A lot of the bad press that bamboos have suffered is due to a basic misunderstanding of the nature of the plants. Many gardeners seem to thing of them as shrubs, and, like a shrub, they expect that once they get too large they simply prune back their top growth and keep the to a given space. But bamboos are, of course, grasses, rather than shrubs, and, like all grasses they consist of an underground rhizome and an above-ground network of shoots and stems – the “canes”, technically known as culms. Another key thing to remember is that there are an astonishing number of bamboo species – at least 5000, at the latest count – and these vary from tiny, slender grass-like pygmies to vast, towering, tree-like giants from which entire houses are built. So when a gardener asks about how to solve problems with “bamboo” it’s pretty important to know which bamboo they’re referring to.
From a horticultural perspective you can very broadly divide the species into two simple groups – the clumpers and the runners. Clumpers are defined by having a very tight, non-spreading rhizome system from which the culms arch outwards, like a fountain. These species are, by definition, entirely non invasive, but this also makes them rather difficult (or at least slow) to propagate, since the very congested rhizomes are hard to work with and difficult to divide. The runners, by contrast, have entirely erect culms that emerge in a line from their spreading rhizomes. When growing vigorously, and without major competition these rhizomes will spread out in all directions from their central start-point, and produce curtains (bamboo curtains?) of culms along their routes.
So here’s where gardeners have to bite the bullet. Realistically, no running species of bamboo is remotely suitable for planting in a regular sized garden without being containerised beneath the ground to reduce the spread of the rhizomes. Yet it is exactly these running species that are most frequently offered for sale, in part because of the great beauty of some of them, but mainly because of their ease and speed of propagation – in other words nurseries can make more plants, and so more money, more quickly from these species.
In a parkland or large country garden where they can reach their full potential these running species are truly magnificent. Best known amongst them are the Phyllostachys species – large (often very large) bamboos some of which have gloriously coloured culms of yellow, green, purple and black. Phyllostachys nigra – the black-caned bamboo – is viewed as a near-essential element in many fashionable garden designs, and is particularly popular in urban settings. It’s the least vigorous, and also one of the smallest of the Phyllostachys, but will still form an extremely substantial plant of tree-like proportions in just a few years when planted in open ground, as well as running in all directions when left unchecked.
I am partial to Phyllostachys myself, and have a collection of them in the garden, but here they have 5-or-so acres in which to make a home, and even then they need much annual work to keep them in place. So instead of attempting to tame these wild beasts of the garden, I would always recommend selecting and planting only the clump-forming species of bamboo. Many of these are native to higher elevations in China and the Himalayas, and the best of them can easily rival or indeed surpass the appeal of the best of the Phyllostachys species.
One of these clumpers is, in fact, very widely available and gardeners should have little trouble finding a specimen even in non specialist garden centres: Fargesia nitida was one of the first bamboos to be introduced into Western cultivation, with seed arriving in Europe towards the end of the 19th Century. It is a small to medium sized species, reaching around 4 metres, although often no more than half this height. The culms are slender and often arch over, affording the entire plant a airy, elegant appearance. Best of all, though, the culms vary from deep black-ish purple though to rich red, particularly when the plants are grown in full sun, making F. nidita an eminently suitable replacement for it’s towering black-stemmed cousin Phyllostachys nigra.
Fargesia is home to an array of other very beautiful bamboos, many of which have only recently been introduced into cultivation. F. perlonga, F. rufa, F. fungosa and F. yulongshanensis are all very fine, smaller species, well worth seeking out for their intricate charms. On an entirely different scale is Fargesia utlis. This ultimately becomes a very large plant, but is still confined to a tightly clumped centre from which the culms arch outwards like an exotic green fountain. The species is too big for use in the border, but makes for a magnificent lawn specimen.
Drepanostachyum and Himalayacalamus are two closely related Himalayan genera, all of whose species are very beautiful, if somewhat less hardy than the Fargesias. D. falcatum has narrow culms that age to bands of crimson, yellow and green, H. falconeri has culms heavily striped with cream, whilst those of D. hookerianus emerge with a waxy blue sheen and age to deep red in the sun.
My favourite genus of bamboo, and the one that I would never want to be without in this or any other garden, is undoubtedly Thamnocalamus. These are hardy, high-altitude, clump-forming bamboos, primarily native to the temperate forests of the Himalayas. T. spathiflorus has culms that age to burgundy, whilst in T. aristatus they become clear yellow.
Finest of all, however, is the highly variable T. crassinodus, in which the culms typically emerge powder-blue, strongly contrasting with their protective, papery, fawn, sheaths. Some forms of the species maintain their white-blue powder covering to maturity, whilst in others, such as ‘Kew Beauty’, the culms turn to a deep red when grown in good light. All have the most beautiful, narrow leaves, that help to create a particularly beautiful impression both up-close and at a distance.
There are many other worthy and hardy clump-forming bamboos too, but my overall plea would be to take the time to investigate the possibilities that these plants have to offer, and then seek out the best to suit your space as well as your tastes. It may take more time and potentially more money at the outset, but the long-term results will repay the initial outlay and effort many times over.