It has a 53-year history. After Robyn's resignation, it went into recess until Margi Keys agreed to take over as secretary. She plans to revitalise it and wants to attract new members.
Colin Ogle was the "guru" of the group, Keys said. But he puts it another way.
"It was always that we shared knowledge. There are always one or two that know a bit more than most of the others."
Founding members of the group include the late Joan Liddell, Arthur Bates and Neill Simpson.
Colin and Robyn were members of the Wellington Botanical Society before arriving in Whanganui in 1989. They arrived with knowledge of native plants and learned about exotic ones from people like Vonnie Cave, Clive and Nicki Higgie, Jim Howard, and Ian and Jocelyn Bell.
The Whanganui group had monthly meetings and field trips to places like Mt Ruapehu and Whitiau Scientific Reserve. In the Ruahine Forest Park members climbed through bush to scrub and out into alpine vegetation. They explored the herb fields at the top of Taranaki coastal cliffs.
Arthur Bates wrote the group's history on its 25th anniversary, and it celebrated 50 years' existence in 2018. It has 15 paid-up members, and 63 who receive notification of events.
Its life members are Neill Simpson, Colin and Robyn Ogle and Ian Bell, and Bell said the Ogles' devotion had helped it survive. The chairman is Clive Higgie, with Lyneke Onderwater as treasurer.
These days it is one of three Whanganui organisations that provide Nature Talks in the Whanganui Regional Museum lecture theatre. It also meets every two months and has social events and field trips. They might be to a wild place, or a weedy place, or a simple wander through Gonville streets to see what is growing in gardens.
The next field trip will look at plants on the true left side of the Whangaehu River estuary. To find out more, email wbotgp@gmail.com.