The Nuytsia floribunda is significant for its rarity at a State level. This tree is in the Mistletoe family and is extremely rare in cultivation due to the great difficulty in growing-on specimens to a mature size. The specimen is approximately 34 years old. It is the most southerly growing specimen in the world and one of only a few known to be in cultivation outside Western Australia.
The Australian Garden has been developed on a site which was originally a snad extraction area operated by Cranbourne Sands from the early 1920s. The land was a portion of a Commonwealth Military Reserve, purchased by the Government of Victoria in 1970 for the Royal Botanic Gardens Melbourne (RBGM) to establish a Botanic Gardens and Research Institute, dedicated to the growing and research of Australian native plants.
From June 1976, experimental plantings commenced to ascertain what plants would grow in the remaining siliceous sands on the site. Although often problematic in Victorian conditions, Western Australian plants proved to grow particularly successfully on the site. With the proven success growing Western Australian native plants in the Cranbourne sands, it was decided to continue to experiment and broadly diversify the palette to verify the range of taxa which could be grown successfully, in anticipation of a botanic garden dedicated to the cultivation of Australian native plants.
In 1979, the Assistant Propagator in the RBGM nursery, W. Worboys was given a large bag of seed of Nuytsia floribunda from Western Australia, brought back from Perth by the Director, Dr. D. Churchill. Some of this seed was sown and germinated in community pots and pricked out into tubes to grow on. Other seed was taken to the RBGC site and hundreds of seeds were direct seeded around the roots of a diversity of existing cultivated plant species which had been growing since 1976. Over the next three years, fresh seed were obtained and germinated and/or direct seeded in a variety of ways including direct seeding into pots of established plants.
The immediate area where the Nuytsia floribunda is growing was variously direct seeded and planted with tubed seedlings of the species. It is unclear from which method of propagation the current tree arose. This area is a sandy knoll perched above the surrounding, which was sparsely vegetated by indigenous species Heath Tea-tree (Leptospermum myrsinoides) and Sandhill Sword-sedge (Lepidospermum concavum) and introduced weeds Annual Veldt-grass (Ehrharta longiflora), Couch Grass (Cynodon dactylon), and sparse seasonal growth of Cape Weed (Arctotheca calendula). It is unknown which species root system was parasitised by the Nuytsia.
For approximately five years, the seedling remained a single stem (to 25cm tall) then it started producing numerous, apparently adventitious root suckers across and area of approx. 0.3 square metres, but all the suckers still remained only 25cm tall.
By approx. the 12th year after germination, the suckers were covering 1 metre square. Then one sucker started to dominate, and grow to form an upright stem. This stem developed into the trunk while the surrounding suckers disappeared. In late Dec 1996, the first flowers were observed, with a few flower shoots scattered across the top of the tree. The following year no flowers were observed and over the ensuing six years flowering was irregular. Since 2003 the summer flowering has occurred annually and the number of flowers across the canopy has continued to increase.
The landscape design of the Australian Garden has been significantly influenced by the presence of the Nuytsia floribunda due to its rarity. The Howson Hill garden precinct was designed to display Mallee species in a naturalistic landscape with the Nuytsia being protected with important hydrozone and tree protection zones during the landscape construction of the Australian Garden between 2003 and 2012.
Western Australian Christmas Tree (Nuytsia floribunda)
For a full description of Nuytsia Floribunda go to: http://bioweb.uwlax.edu/bio203/s2009/mortense_jord/.