Hilton Hotel “green wall” reinvigorated
Sydney’s Hilton Hotel, built in 1969, was for several decades a triumph of concrete over style. Passing into the ownership (not just management) of Hilton International in 2000, it was redesigned to improve both its look and its patronage. In July 2005, it was reopened with a radically improved design. One striking feature of the new design is a “street” that passes through the hotel between Pitt and George streets. This street brings visitors into a courtyard and a glass-fronted main entrance, opposite which a vertical garden cascades 11 storeys.
TLC Indoor Gardens installed this “green wall”, planting Cissus rhombifolia. When first installed, it looked eye-catching and grew well, but around 12 to 18 months later it started to decline. The landscape architect called in SESL to investigate in 2008 with a view to reinstalling the green wall.
We found that the normal organic potting medium they had used had decayed and collapsed, causing waterlogging. This was the principal cause of the decline.
Simon Leake, SESL’s founder and a member of the Australian Standards potting mix standard committee since 1989, designed a special-purpose long-lasting mix using highly specialised components not normally used in the potting mix industry. These included diatomaceous earth screened to precise dimensions, and other organic and mineral components. The mix is designed to retain its physical structure for at least 5 years, thus retaining water while preventing waterlogging. Although made mostly of mineral components, it has outstanding water- and nutrient-holding ability.
TLC Indoor Gardens have now reinstated the green wall, as the photo (taken last week) shows. (The photo was courteously supplied by TLC Indoor Gardens.)
Specialist knowledge
Green walls are expensive installations, so it can be very disappointing for our clients to see them fail within a year or so, having spent so much money. The growing medium is the lowest-cost component, but it is also the most likely component to fail, and its failure usually means the end of the installation. This sort of mix design lies outside the expertise of the normal nursery and potting mix industry and requires highly specialist knowledge of the sort that SESL can provide.
Further reading
Weirick J. 2006. Johnson Pilton Walker’s redevelopment of the Sydney Hilton is a work of urban architecture that makes a significant contribution to the city. Architecture Australia Jan/Feb.
TLC Indoor Gardens: http://www.tlcindoorgardens.com.au/