English

Noun

clumper ‎(plural clumpers)

1. A grass or other plant that tends to form clumps.
   • 2007 July 5, Anne Raver, “A Cane the World Can Lean On”, in New York Times:

     Bamboo can be as delicate as the umbrella bamboo, Fargesia murieliae, a clumper with soft pea-green foliage and a weeping habit, or as heroic as Phyllostachys edulis, whose sturdy olive-green canes can grow 70 feet in a single season.

Etymology 2

Compare German klumpern ‎(“to clod”). See clump (noun).

Verb

clumper ‎(third-person singular simple present clumpers, present participle clumpering, simple past and past participle clumpered)

1. (obsolete, intransitive) To form into clumps or masses.
   • (Can we date this quote?), Dr. H. More

     Vapours […] clumpered in balls of clouds.