Bamboo: how destructive is it, really?

Anxious garden owners often ask me this question, or variations on this theme: is it safe to plant a bamboo in a smallish garden?

They are right to be concerned: I have seen scary bamboo groves, where the garden has all but disappeared, the neighbours are furious, and threatening legal action because the Bamboo is invading their gardens as well.

There are basically two types of bamboo - runners, and clumpers. Clump-forming bamboo are the well-behaved ones: as the name suggests, they form a clump, self-contained and tidy. Bamboos which are described as runners, or "non-clump-forming" are the invasive ones which will quickly become a nuisance, if you have a small garden. 

So read before you buy: look at the proper name, the "latin" name, of any bamboo which you are thinking of buying, and look it up on the internet to see if it is a clump-former, or not. 

One of the best ornamental bamboos, in my opinion, is Black Bamboo, proper name Phyllostachys nigra. It's not cheap to buy, because it is slow-growing: the plant which is on sale may have taken several years to attain that size. It's also expensive because it is beautiful! The stems start off green, but as the leaves open, the stems turn a gorgeous glossy black - every time I thin mine, they are pounced on by a local flower-arranging lady.  And they are almost evergreen - in a fairly mild winter, they keep their leaves, so they are interesting all year round. 

Here is my own black bamboo, normally just about reaching the upstairs windows, but on this day, bent double by the snow. Yes, this photo was taken in winter.... but you can see that it still has leaves, under all that snow.

(I thought we might all enjoy a picture of nice, cold snow: as we are in the middle of a hot spell at present!)

However, be aware that even a well-behaved bamboo such as this one can, in time, become a bit of a monster: one Client hired me to dig out the outskirts of her Bamboo which, after 30 years, had formed a clump which must have been 12' (4m) across.  That was an afternoon of pickaxe and sweat, I can tell you!

The standard advice is to dig a hole for your new bamboo, then line it with something strong and impermeable, such as thick plastic, or metal.

I find that old water butts are quite good for this purpose: they are super-strong plastic, and they come in convenient-sized hoops: all you have to do is get an ordinary woodworking saw, and gently rub it across until it "bites", then simply saw through the plastic.

The ones in this picture - right - were for a Mint bed, and if I were intending to use them to restrain bamboo, I would make just two hoops, not three, so they would be deeper.

Again, though, a word of warning: this will work for several years, but eventually the bamboo will find its way out of the bottom of the hoop, and will escape into the wild. 

However, even if that happens, it is a lot easier to dig it out when most of it is contained within the hoop.

If you can't quite visualise what this would look like in a garden, here - left - is one of the above hoops, buried vertically in my friend's herb bed, filled with soil and waiting for the mint to be planted within it.

In my experience, a newly-bought black bamboo will be perfect for at least 10 years or so, and then it will start to settle in, and get "big" - and in another few years, it will start to get "too big". 

When this happens, it is possible to thin out clumps of bamboo, which is done by sending your brave Gardener in to the clump, armed with a machete and a packed lunch, and instructing them to cut out some of the oldest stems, from the centre of the clump. This reduces the density, making them less overpowering.

A refinement of this technique is to instruct your Gardener to clip off all the lower leaves, from all the stems:

.... a tiresome job, but as you can see - right - you end up with something much tidier, and this process also allows light to reach the area below the bamboo, as well as restoring a feeling of space and elbow room, to your garden.

(I would just point out that in this case, I took the photo before I had cleared up all the mess underneath: it looked so much better once I had raked out all the debris!)

 

In fact, if you want to take this idea as far as it can go, how's this - left - for the ultimate Repressed Bamboo Installation? 

They have been planted in a very narrow raised bed, and the lower leaves have all been stripped off.

OK, that's a step further than I am prepared to go, personally: this was taken at a show garden, and I have doubts about the wisdom of covering the soil with white stone chips, partly because they are going to absorb a lot of heat - assuming that the sun shines on that side of the garden - and bake the poor bamboo roots: and partly because it is going to be a constant battle to keep it clean and pristine, once the bamboo starts shedding leaves. 

On a purely horticultural note, I would also say that the raised bed is very narrow indeed, so I doubt the roots of the bamboo have much soil - although, on reflection, is that a bad thing? It will suppress their growth, I suppose -  and they are not going to get much rainwater either: although, again, that might be a good thing, if you don't want them to grow too vigorously. And, personally, I would expect a garden which has been this highly "styled" to have irrigation.

Ah, and now we get to the point of this article - destructiveness of bamboo. Mythbusters explored the story that Japanese prisoners of war were tortured by being tied down over a bed of bamboo, whose shoots would pierce their bodies and very slowly kill them. It is, apparently, feasible: the shoots of large bamboos are strongly pointed, and can grow quite literally inches, every day. Nasty! 

Now, remember my own black bamboo, covered in snow, earlier in this article? Well, having been a perfectly behaved clumper for many years, it's finally started making a bid for freedom, and has started to send up runners.

I was sorting out that corner of my garden the other day, preparatory to repainting the woodwork, and noticed this - left.

Can you see that tall, thin, upright thing in the middle? It's a bamboo shoot, coming out of the wooden corner post...

To be fair to the bamboo, this corner post was already quite cracked, but look! The bamboo is forcing its way up along the line of weakness!

I am not entirely sure how I am going to deal with this: I don't really want to have to lift all the shingle, pull back the membrane, trace back the root and cut it off, close to the parent plant.

But I can't use any sort of weedkiller, because this shoot is still attached to the main bamboo, and I certainly don't want to kill that one off.

For now, I have truncated it, chopping of off short: but of course that won't stop it, and in no time it will regrow, and then I will have a tuft of foliage, instead of a single shoot. 

Heyho.

I suspect that I will have to undertake the excavation route: it's the only way (apart from nuking them from orbit, of course) to be sure. But it's a timely reminder that even the best behaved black bamboo will, if you leave it long enough, start attempting to take over your garden.

Long story made short:  some bamboos are worse than others and if in doubt, grow them in a large pot, up on feet!

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