The Australian National Botanic Gardens was established to grow the Australian flora and this specialisation has encouraged experimentation in cultivation techniques. In turn, this led to the development of the wide range of specific horticultural practices now used in the maintenance of the living collections. Practices developed by the Gardens include specialised field collection and transport and handling techniques, involving full documentation of locality and growth habit and especially features of the plant's habitat and microhabitat as a primary source of horticultural indications.
Specific propagation treatments and techniques have been developed for many recalcitrant groups for which grafting may be required to ensure the survival of species that lack vigour or are prone to root rot.
Many Australian plants are adapted to soils of low fertility but benefit from additional nutrients; for some, however, even moderate levels of some nutrients may be toxic. Drainage and soil improvement is often required at the Canberra site, where, in spite of slopes, there are many poorly drained areas. Raised beds have had to be constructed to create growing conditions suitable for many difficult species.
Pruning, ranging from delicate tip removal to coppicing at the base, is important for amenity shaping and cultural maintenance. Tree surgery is carried out to remove trees or limbs in danger of falling or where necessary to `balance' a tree.
Manipulated-environment structures such as glasshouses and coolrooms are used to house species that will not survive outdoors. Shade cloth and Solarweave are used to cover other areas, to protect plants from excessive solar radiation, precipitation and frost.
The recording of techniques developed for the cultivation of the great range of species in the living collections is a potentially very valuable contribution to the horticultural treatment of the Australian flora. Unfortunately, a lack of resources means that this potential is not being realised.
The Gardens previously conducted a program of applied horticultural research but reduced resources have constrained research activity. The recommencement of applied horticultural research is a priority for future development.
Ways of improving the efficiency of water use will be examined and high-volume irrigation systems will be replaced with low-volume and micro-irrigation systems. Improved drainage techniques will also be investigated and further plant species suitable for poorly drained soils will be sought. The aquatic areas will be better utilised to grow a wider range of taxa; for example, plants associated with waterfalls and swamps.
In the glasshouses environmental controls will be more finely tuned, to better emulate the natural environment of the species housed. The coolroom will be extended to house a larger collection of subantarctic plants.