Local grower and shower Wayne Hughes is one of the organisers of the annual summer event.
Mr Hughes has been involved in the game for more than 40 years and said this season had been particularly difficult for serious growers: "We had five slight frosts on end in November. They weren't big frosts but they were enough to set things back a bit."
Despite that hiccup, he said, they were expecting some of the best blooms on show in the city on Saturday for judging, provided by growers and enthusiasts from New Plymouth down to Wellington.
"We're expecting some great dahlias and gladioli, especially. Wanganui is noted as one of the best gladiolus-growing areas in the country," Mr Hughes said.