Cultivation notes
Bamboos thrive in moist, but well-drained soil in a sheltered, sunny spot. They tolerate most soil types, but some, such as Shibatea, require acid soil or ericaceous potting compost. Bamboo will grow in poor soils, but not in constant wet, boggy or extremely dry conditions.
Plant in spring so that energy stored in the bamboo's rhizomes is used to produce strong, new canes in summer. These rhizomes then produce roots before the plant becomes dormant from autumn to spring.
Before planting, dig in well-rotted garden compost or manure to raise the organic content of the soil. This will also improve its ability to hold moisture.
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 (note: may remain clump-forming in poor or dry soils but can become invasive in warm, moist or favourable conditions), 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
Plant in spring so that the food reserves in the rhizome are used to produce a good flush of fresh canes in summer.
- Dig the soil over and add organic such as well-rotted manure or garden compost to condition the soil and improve its water-holding capacity
- The planting hole should be dug so that the rootball sits slightly low, with 2-3cm (1in) of soil covering the original surface
- When filling in around the rootball and firming with the soil and compost mix, take care not to damage the young rhizomes
- Water and mulch after planting
Watering and Feeding
- Water regularly during dry periods
- Bamboos require a high level of nitrogen in spring and a balanced fertiliser through the rest of the growing season until late August
- Allow bamboo leaves around the plants. This foliage contains silica which helps provide strength and stability
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 1.2m (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 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. Ensure that bamboo plants in containers do not try out in winter, however, since the foliage is prone to wind scorch.
In very cold weather, insulate containers with bubble wrap or move them to frost-free conditions.
To ensure fresh new growth, divide the bamboo every couple of years using a saw to cut through the rootball, retaining the younger rhizomes and canes.