tumbleweed

Short definition from Wiktionary

Noun

1. 1
   Any plant which habitually breaks away from its roots once dry, forming a light, rolling mass which is driven by the wind from place to place; as Russian thistle, wild indigo, witch grass, Amaranthus albus, etc.
2. 2
   Describing unwanted silence and inactivity. Often used of a situation when one makes a statement that is ignored or ill-received by one's audience, as the resultant silence is likened to that of a desolate desert with rolling tumbleweeds.
3. 3
   A tan colour, like that of a tumbleweed.