"... be sure to tune in next time when we'll be discussing ... what to do if muggles hear your Honking Daffodils..."
-- Tilden Toots, "Toots, Shoots n Roots" radio show
A magical flower that honks.
- Professor Sprout grows these, but Lavender Brown says she prefers mundane daffodils to take as a gift to Professor Trelawney, who had just lost her job as Divination professor (OP27).
- A wizard growing these in his garden may encounter a problem with Muggle neighbors hearing them, according to the radio program Toots, Shoots 'n' Roots (JKR).
The daffodil flower has a central part known as the "trumpet," so we can assume that a Honking Daffodil sounds off on the trumpet.