Cultivation notes
Bamboos thrive in moist, but well-drained soil in a sheltered spot. They tolerate most soil types, but some, such as Shibatea, require acid soil or ericaceous potting compost.
There are bamboos for nearly every garden and here are some popular choices:
- For a shady spot: Chimonobambusa
- For direct sun: Phyllostachys
- For an exposed site: Bashania, Pseudosasa, or Sasaella (and consider erecting a temporary netting windbreak during plant establishment)
- For any garden: Pseudosasa and Indocalamus are completely unfussy
Types of bamboo
Bamboos are either classed as running or clump-forming bamboos.
Running bamboos, also known as invasive bamboos, produce long rhizomes (underground stems), which grow away from the main plant and will spread rampantly if not contained.
The following are running bamboos: Arundinaria, Bashania, Chimonobambusa, Clavinodum, Hibanobambusa, Indocalamus, Phyllostachys, Pleioblastus, Pseudosasa, Sasa, Sasaella, Sasamorpha, Semiarundinaria, Sinobambusa and Yushania.
Clump-forming bamboos grow in tight clumps and are less invasive and include: Bambusa, Chusquea, Dendrocalamus, Drepanostachyum, Fargesia, Himalayacalamus, Schizostachyum, Shibataea and Thamnocalamus.
Planting inside a physical barrier
New bamboo plants or divisions can be contained within a physical barrier to prevent them spreading through beds and borders.
- Dig a trench at least 60cm (2ft) deep, but ideally 120cm (4ft) deep
- Line the sides of the trench with either solid materials (such as paving slabs, corrugated iron sheets or pre-cast concrete drain sections) or with fabric (such as root barrier fabric obtainable from Green Tech Ltd or industrial linoleum (2mm (1/8in) thick), available from builders merchants). Butyl pond liner is not suitable, as the bamboos’ underground stems can penetrate this
- Fabric ends should be overlapped by at least 30cm (1ft) and bonded with appropriate mastic
- The barrier should protrude at least 7.5cm (3in) above soil level, to prevent the bamboo stems arching over the top. The protruding edge can be disguised with decorative mulch or stones
- The planting hole should be dug so that the rootball sits slightly lower than the original depth, with 2-3cm (1in) of soil covering the original surface
- Firm well when backfilling, taking care not to damage the young rhizomes
- Water well and mulch after planting
Container cultivation
Smaller bamboos make ideal container plants grown in a large pot (at least 45cm (18in) across and deep) in loam based potting compost such as John Innes No 3.
When planting, incorporate controlled release fertiliser pellets and water retaining gel in the compost. During summer, water frequently and feed with a liquid feed regularly. Reduce watering and stop feeding in winter.
Routine bamboo maintenance
With a little effort it is easy to keep bamboos looking good and prevent them from becoming a nuisance in the garden.
- In spring, remove any weak, dead, damaged or spindly canes, cutting them to ground level with secateurs or loppers
- At the same time remove any debris at the base of clumps
- To show off plants to their best, remove some of the foliage from the bottom of the canes. Either snap the side branches off with a swift downward motion (wearing gloves) or cut them back with secateurs, pruning as close to the main cane as possible to leave a smooth finish
- Irrigate in dry spells, as bamboo prefers moist but well drained conditions
Bamboo flowering
Contrary to popular myth, bamboos do not always die after flowering, although the chances of full recovery are not good. They flower infrequently and it can be dramatic, with browning of the foliage and development of tall, feathery, grass-like flowers. Flowering can weaken a clump, but the following steps may result in recovery:
- If you see the odd flowering shoot, cut it out promptly to discourage more from forming
- If the whole clump starts flowering, allow it to do so undeterred, even if the clump looks terrible. Continue to feed and water. The following spring, cut back the clump to ground level and feed with a high nitrogen fertiliser such as a spring lawn feed to encourage new green growth from the base