A "gardener" comes to a lady, offering many flowers if she will marry him. She is not interested.
One can only suspect that this piece was made up to get in as many flower symbols as possible; at least, there seems little point to most of the imagery. For a catalog of some of the sundry flower symbols, see the notes to "The Broken-Hearted Gardener."
Child prints a text (additions and corrections to "The Gardener", p. 258 in Volume V of the Dover edition) which conflates this with "In My Garden Grew Plenty of Thyme" or something similar.
The song is also sometimes confused with "The Gairdener and the Plooman" (which see). - RBW