South Africa's oldest greenhouse, built at the turn of the last century, is under threat. The historic structure forms the heart of a plant nursery run by Cape Town horticulturalist Kate Mason at Montebello Design Centre in Newlands.Now the greenhouse is at the centre of a battle between people like Mason, who view it as a national treasure, and those who wish to see a multipurpose conference centre built in its place.The new structure would "destroy an incredible piece of history and heritage", said Mason.Plans include demolition of most of the greenhouse to make way for a double-volume barn-like structure.The footprint would be 50m² bigger and would include an ablution block.Mason said the development would "change the look, feel and nature of Montebello", which was a "rustic haven in the middle of a busy urban setting".It could cost the design centre its visitors, who make an outing of eating at the restaurant, visiting the nursery, chatting to wood carvers, and browsing in arts and crafts workshops.Mason said that even if the battle cost her nursery its tenancy at the design centre, she would count it a victory if the greenhouse was preserved.But Montebello MD Tessa Graaff, who had the plans drawn up, said the proposed development spoke to the "core purpose" of Montebello, which was to "nurture dreams and grow creative solutions from Africa".It was all about "seeding new ideas", she said."We could just keep restoring it, but what is the point of that?" she said. "Kudos to us that we have kept it going, but it is now in a state of danger to the public and is in an imminent state of collapse."full_story_image_hleft1But according to the most recent structural engineering report, in October last year by engineer Garry Sheard, as long as certain measures were put in place, "we are satisfied that the glasshouse is safe for public access for the foreseeable future".Mason said restoration would be "a fraction of the cost" of development, and objected to the way the maintenance levy she had been paying to Graaff for almost a decade - amounting to about R135,000 - had been used to pay the architect who drew up the plans for the new development.Mason said that in the 11 years she had been at Montebello, Graaff had commissioned just one paint job and minimal one-off measures to "stabilise" the greenhouse."It upsets me that money meant for maintenance and restoration went towards drawing up plans that work against the greenhouse existing at all," she said.Restoration would cost around R500,000, but plans she had seen for the "reimagining" would well exceed that.Graaff confirmed the levy was used to pay for the architect's plans.Although plans had "not yet been passed by Heritage [Western Cape]", she had met officials of the City of Cape Town and the provincial government for initial discussions, Graaff said.Zwelibanzi Shiceka, of Heritage Western Cape, said the organisation's only involvement with the greenhouse had been over an application to stabilise it last year.full_story_image_hright2The application was deemed incomplete as the University of Cape Town - which owns the land - had not sought input from the Newlands Residents Association, and had been asked to do so."Since then, no communication or a response has been received from UCT," he said.UCT spokesman Pat Lucas told the Sunday Times: "Montebello is free to make any necessary changes to the space, provided it obtains all necessary official approvals."The residents association said it had not been approached for comment but "if any changes went ahead without [our] input, it would constitute a serious problem - not only legally but also because many of those in the association are extremely heritage conscious".sub_head_start A potted history sub_head_end• 1764: The Montebello homestead and stables were built. The land belonged to the first brewer in the area, who used spring water.• By the turn of the 20th century, Montebello was the residence of the owner of Ohlssons Brewery (today Newlands Brewery) which was on the same estate.• Around 1902, the small greenhouse was built.• In 1980, former owner Cecil Michaelis bequeathed the property to the University of Cape Town.farbert@sundaytimes.co.za..