How to grow bamboo without it taking over your garden
I have distinct memories of my college tutor many years ago (more than I care to remember) becoming aggravated with some of my fellow students who seemed to humanise their plants. My tutor’s response was to inform us all that plants don’t feel happy or sad; their fundamental mission in life is to reproduce, outcompete others and, given half a chance, take over the world. That statement, although shocking at the time, has stayed with me throughout my career.
It’s a reminder that plants want to thrive and grow with as much vigour as possible, whether that be a delicate orchid on our windowsills or a more robust specimen such as the increasingly feared bamboo. Arguably, some plants try to take over the world with a little more panache than others, and although bamboos do need to be managed and planted with caution, they can make incredibly valuable additions to our gardens.
Bamboo facts
Bamboos are actually a subfamily of the grasses, although they have a tree-like or shrubby appearance with woody stems.
The way in which bamboo grows can very much depend on its environment, with plants in more favourable conditions having a lusher appearance compared to those in more impoverished places.
Bamboo is an evergreen plant, meaning that it does not lose its leaves in the autumn and grows fresh ones the following year. In the spring bamboos will have a new flush of leaves which then replace the older ones which gradually fall to the floor.
They are very hardy and vigorous and if a plant is severely damaged it will often recover.
As bamboo shoots emerge from the ground, they tend to have the same girth as the mature cane, compared to a woody broadleaf tree that increases its diameter as the years go by.
Underground stems, which are known as rhizomes, generally grow away from the main clump in order to increase its size and colonise new parts of the garden. As these rhizomes develop, canes will emerge from the ground and generally near the surface, although some species can be up to one metre deep.
The true roots of a bamboo will appear from the rhizome which then supplies the plant with water and food from the surrounding soil.
In Japan people are said to flee into bamboo clumps during an earthquake because the soil is so tightly bound in the network of rhizomes.
Growing bamboo in containers
If you have a general appreciation of bamboos and would like to grow some in your garden, but have an underlying concern that they may cause you problems in the future, then why not consider growing them in a container? Bamboo is a vigorous plant and they very rarely do well in a small container, so try and use the largest container that you can practically manage – a minimum of around 50 litres in volume would be worth considering.
A larger pot will support a more magnificent specimen as thirsty and under fed bamboo can look underwhelming. Most bamboos will be quite happy in a container with reasonable drainage, although they are robust, a waterlogged container during the winter will often kill off a young, establishing bamboo clump. Consider dividing the clump every few years, maintaining a manageable size and keeping the young plant in good health. An important factor in growing bamboo in containers is not allowing the plant to dry out, although frustrating, the advice would be to keep the bamboo moist during the growing season, but do not allow it to become waterlogged in the winter.
How to keep bamboo under control in the garden
I am a big fan of the coloured stemmed phyllostachys, commonly known as the black bamboo or yellow caned bamboo. These evergreen plants can fulfil a useful function in a garden, similar to a small tree, with year-round interest, colourful stems and a sturdy nature. It is perfectly feasible to grow these plants and enjoy all of those merits, but we need to appreciate that these bamboo plants need to be monitored regularly, otherwise the consequences can be far reaching and backbreaking.
Every autumn, I remove the lower leaves of my phyllostachys clumps to about two metres from the ground. This allows me to appreciate those coloured canes. Any weak or damaged canes can be removed to give a more transparent effect to the plant, and also increase the size of the canes that remain. Finally, I take a garden fork and cultivate around the edge of the clump, this will expose any of the surface-dwelling rhizomes whose mission it is to dominate that particular part of your garden. By lifting these rhizomes and cutting the main clump back with a pair of loppers, we keep our bamboo a manageable size and prevent the clump from becoming out of hand. By annually curtailing these bamboo plants we can keep them under control and enjoy the many merits that they offer us as gardeners.
Runners and clumpers
Bamboo can be loosely divided into running and clump forming types. Running bamboos are very difficult to control and can spread aggressively, inhabiting a large area in a short period of time. Although less favourable conditions can slow them down, if their environment improves, then their rhizomes can sprint across your garden by over a metre or two in a year. I’d avoid pseudosasa japonica (AGM), pleioblastus variegatus (AGM) and sasa veitchii.
Clump-forming bamboo will still need monitoring and controlling. I always think of “clump forming” to mean a clump of five metres squared, given half a chance and the right conditions. Managing your bamboo annually can alleviate any concerns and some that are worth considering are phyllostachys nigra (AGM), chusquea culeou (AGM), phyllostachys vivax f. aureocaulis (AGM) and fargesia “red panda”.
How to irradicate bamboo
Cultural control
Another way to put “cultural control” would be “digging”. Bamboo can be dug out either by hand or mechanically with a small digger. Small clumps on the end of a runner can be removed reasonably easily, but for any sizable clump, I’d suggest contacting a professional or hire company. Remove as much material as possible and stay vigilant for any stragglers over the next year or so.
Weedkiller control
Glyphosate-based herbicides can vary in their effectiveness to kill bamboo. The larger the clump, the more persistent and resilient they are. It may take several applications to kill the bamboo completely. As the whole clump will be connected, sever any unwanted growth from the rhizome attached to the mother plant before applying your weedkiller. To kill off larger clumps, cut the canes to the ground and apply a stump and root killer to the emerging foliage, several treatments may be needed.