Strung out in the greenhouse

The assignment for my four-hour volunteer shift at the University of Minnesota Conservatory greenhouse was clearly listed on a whiteboard, with my name attached. Since most of the tasks involved working with strings of overhead cables or air tubing, much of my shift was spent at the top of a ladder.

Vining plants are limited to only a few of the many benches in the greenhouse. Steel cables are strung above the benches to support their growth. Because many plants grow in a small space, part of the challenge is to untangle and separate the vines so that they don't strangle each other.

Not many of the vines are blooming at the moment, as it is winter. However, Thunbergia grandiflora is producing a few lovely blue flowers (its tendrils grow clockwise, hence the common name Bengal clockvine). It's a popular houseplant, but it has become an invasive weed in parts of the world, like Australia, especially around waterways.

Thunbergia grandiflora; notice small brown scale insects sucking sap on the stem

A trusty light-weight ladder allows access to the overhead vines

Another vining plant that requires occasional adjustment and cleaning is a climbing palm. Members of the Calamoideae family are the source of rattan fibers, used in furniture construction. They mostly grow in Southeast Asia, but also in parts of Africa.

A climbing palm loops around an overhead steel cable; an African rosemound tree blooms nearby.

In another section of the greenhouse, a chronically clogged water pump has been replaced with a new air bubbler. It sits in a submerged water tank used to grow a type of conifer that prefers its roots in running water. Bois bouchon in French, or cork wood in English (Retrophyllum minus) is endemic to the island of New Caledonia in the South Pacific, where it is threatened by habitat loss.

To reach the new bubbler, a line of tubing has been strung across an adjacent room to a compressed air fixture. My task was to secure and tidy the line as it ran overhead above a doorway, then down along the base of a fence, and finally into the water tank.

The only conifer adapted to grow with roots in running water. Note the blue tubing connected to the new air bubbler.

 

The greenhouse is equipped with a source of compressed air, used for aerating a water tank via blue tubing.