The begonias usually bloom about mid-to-late March, after the Ballarat Begonia Festival.

Robert Beard, the supervisor of Parks and Gardens with the Hepburn Shire Council, said the hot weather in November and the recent humidity may have contributed to the early blooming.

"Coming from South Africa they do like those conditions," he said.

"They're the best I've seen in about eight years."

Mr Beard said there were about 300 flowers in the glasshouse display.

There have been tuberous begonias in the Wombat Hill Botanic Gardens since the 1880s.

The current collection dates back to 1956 when the then gardener and later curator Alf Headland found two remnant tubers in an old woodshed in the gardens and commenced propagation.

He continued to care for the begonias long after his retirement.

Mr Beard also has a long connection with the Wombat Hill Botanic Gardens and the begonia display. Originally hired to help keep the gardens clean, come May 2 he will have worked in the gardens for 32 years.

Mr Beard said it took a big commitment to maintain the display and he paid tribute to the work of gardeners Jock Chase and apprentice gardener Matthew Young for their year-round care of the collection.

Mr Beard said the display would last until April or May, depending on the weather.

After that, the plants enter their dormant phase and gardeners will remove and store the tubers.

The glasshouse was built in Australia's bicentenary year in 1988, specifically to house begonias.