Early in the 1900s Burncoose Gardens was believed to have a collection of over 100 species of bamboo. The gardens supplied Sasa palmata to London Zoo for the pandas to eat until the 1960s. However, in more recent decades, bamboo species have been classified, reclassified, and consequently renamed, several times. This has amalgamated what were once thought to be separate species and some would have been too tender to survive occasionally very cold winters. Others will have flowered and completely died as three species have in the author’s lifetime (Fargesia murilae, Pseudosasa japonica, Fargesia nitida). Today we can only claim to be growing around 25 species in the gardens here.
In the Himalayan mountain ranges bamboos set seed en masse very occasionally: say every 70 to 100 years. Most species then die after flowering although they do produce huge quantities of seed which quickly germinate. Many, or almost all, these seedlings immediately themselves flower and die as well. Clearly this causes severe starvation for the Chinese pandas which eat only bamboos. Just a few seedlings grow on again to maturity. Fifty years ago Pseudosasa japonica was a common Cornish garden windbreak. Today it survives as just a few isolated small clumps after flowering and dying out 20 to 30 years ago. The peculiar thing about these bamboo inflorescences is that they seem to occur in all plants of that one species right across the country. Over a period of a few years small plants in pots flower and die alongside mature clumps in the garden. No one has yet been able to explain how bamboo species communicate this desire to flower and die or quite why.
The first fear when growing bamboo is that they will become too invasive in the garden. While you can obviously cut off and destroy new canes (known as culms) which emerge in early summer from beside a mature clump this may become too big a job and it may be that new canes burst under fences into neighbouring gardens. Perhaps the first thing to consider when growing bamboos is how invasive they are:
The most invasive species
Chimonobambusa quadrangularis – its new canes can appear up to 10ft or more from the original clump
Chimonobambusa tumidissinoda
Species which are useful as a thick clump forming windbreak growing say 10-15ft high
Fargesia rufa
Fargesia murilae
Fargesia nitida
Pseudosasa japonica
Sasa palmata ‘Nebulosa’
Sasa veitchii
Sasa tsuboiana
Species which are clump forming architectural features beside water or in the garden but which are not generally invasive and whose new cane shoots can readily be controlled. These grow 15-20ft tall in the main. These can readily be grown in large deep pots for a few years.
Chusquea coleou
Phyllostachys aurea
Phyllostachys nigra
Phyllostachys flexuosa
Phyllostachys aureosulcata ‘Aureocaulis’
Pleioblastus simonii ‘Variegatus’
Pleioblastus chino. f. elegantissimus
Low growing or dwarf species which are easier to keep under control and which spread more gently
Pleioblastus auricomus
Pleioblastus variegatus
Sasa ramosa
Shibataea kumasaca
The most dwarf and least spreading bamboo which we grow is new and was launched in 2018 at Chelsea. This is Fargesia murielae ‘Luca’.
Then one has to consider how to contain your bamboos to prevent them spreading and getting out of control. One hundred years ago gardeners dug deep trenches around bamboo clumps so that they could cut off any shoots or root shoots which emerged at the edge of the trench. Today some people plant their bamboos into large plastic containers or dustbins sunk into the ground. New shoots from the tallest and more vigorous growing bamboos will eventually force splits in these containers and some are more than capable of sending root shoots through the bottom to emerge alongside. Another solution for some is to sink a thick plastic strip into the ground to a depth of around 3ft around the chosen bamboo plot. This is expensive and a great deal of work probably requiring a mini digger. For lower growing and dwarf species a rather shorter edging of slate or plastic may well do the job perfectly well. So the problem of invasiveness can be overcome but not that easily which is why, in a woodland garden context, you should grow the more ornamental clump forming species in a place where you can admire their culms from afar and where there is room for them to spread.
The graceful arching canes or culms are a fine display in themselves but, phyllostachys varieties in particular, can be shown off to best effect if you spend some time each spring working to show off the wonderful colours on the stems of the canes between the nodes. Clear up any dead leaf material around the base of the clump. Remove any dead canes and prune off all the side shoots on the mature canes up to a height of say 6-8ft. This need not take long but is well worth the effort.
All bamboos grow best in damp or moist fertile soil in a reasonably sheltered position for the more choice species. They are perfectly happy in full sun or partial shade. Those species that make good outer windbreaks are quite happy in full shade where they will perhaps grow and spread more slowly.
Despite the somewhat bad habits of some bamboos species they are some of the hardiest and most popular plants which we grow. Few gardens have no bamboos at all. As they are clump forming division of most species is easy with a strong man and a spade or, as we do it, with a mini digger for the larger clump forming species.