Guide For Planting Sacred Bamboo (Nandina Domestica) On Traffic Islands

The sacred bamboo (Nandina Domestica) is a hardy shrub that grows to a height of 2 m with unbranched stems originating from the roots. The dwarf varieties of this plant are ideal for planting in traffic islands.

Here is a useful guide that will help you do this effectively.

Guide for Planting on Traffic Islands

As expected, landscaping on traffic islands must conform to the policies laid out by respective authorities. This guide is based on requirements set by the Brisbane City Council.

Based on the Brisbane City Council's landscape design manual, Nandina domestica "Nana" is categorized among various groundcovers that may be applied in traffic islands. However, before selecting any plant to use, certain critical factors must be considered. These include:

- The selected plant must not interfere with sight paths at intersections or speed control devices

- The location, shape and form of selected plants should also not encroach on vehicle space.

Generally, traffic islands and medians would comprise both hard surface infill and landscaping. Various other requirements apply to medians (longer traffic islands forming strips in the middle of roads). In case the median has a width below 1.5 m, no landscaping or turfing would be approved on it. Such small medians would instead require concrete infill.

There are various other instances in which landscaping may not be practical. In such situations, hard treatment would be a more reasonable option. Some of these situations include:

- Surfaces with inclines greater than 1V in 3H. Drainage would be a serious challenge in such steep inclines.

- Areas that cannot be conveniently accessed for maintenance.

- Tough areas that would not support healthy plants.

Fortunately, there exist many traffic islands and medians that can comfortably accommodate landscapes. For such islands and medians, various design aspects must be applied, which include:

(i) A median kerb that is keyed 135 mm into the adjacent pavement.

(ii) A concrete backing strip must be present behind the kerb.

(iii) Root barriers may be needed in order to prevent encroachment of roots into surrounding areas.

(iv) A conduit must also be installed to provide easy installation for future tap connection.

(v) An enclosed pipe system installation for discharging of subsoil drainage.

A key aspect in landscaping is the site preparation that involves selection of appropriate soils and soils depths. When correctly prepared, the finished surface would have a mounding feature with a mulch layer covering the top soil. The completed construction may have trees (ranging in height from 1,200 mm and over), shrubs (ranging from 600 to 1,200 mm in height) and ground covers (ranging from 0 to 600 mm in height).

There are several options for planting different plant varieties at speed control devices. Some of these options include:

- Groundcover only, consisting of plants from one species that possess flowers. This treatment has a maximum height of 0.6 m.

- Two shrub species, as well as ground cover. This treatment also has a maximum height of 0.6 m.

- A dense visual barrier created by shrubs, trees and ground cover. This treatment has a minimum height of 1.2 m, but no maximum height. However, the tree canopies should not obstruct vehicle paths.


Keith Kelso enjoys creating beautiful landscapes. His best source for exotic plant species is Nursery Online. They stock some of the best varieties of trees and shrubs. Visit us at http://www.nurseryonline.com.au/nandina-nana-dwarf-sacred-bamboo-200mm/ for more information.