Rhubarb

Rhubarb was a plant. Its stalks were eaten boiled.

Martin Chisom grew rhubarb in Yorkshire inside a forcing shed. A metal bug was able to influence the plants to grow at a high rate and even constrict people, as they did Chisom.

The Third Doctor was able to mediate in a trade agreement wherein Chisom would supply manure in return for "the tenderest rhubarb in the galaxy, grown at a rate unheard of on Earth". (PROSE: Lost in the Wakefield Triangle)