garden plant vs bedder

garden plant and bedder both are nouns.

Word	Noun	Adjective	Verb	Adverb
garden plant	Yes	No	No	No
bedder	Yes	No	No	No

As nouns, bedder is a hyponym of garden plant; that is, bedder is a word with a more specific, narrower meaning than garden plant:

garden plant: any of a variety of plants usually grown especially in a flower or herb garden
bedder: an ornamental plant suitable for planting in a flowerbed

Other hyponyms of garden plant include bedding plant.

garden plant (noun)	bedder (noun)
any of a variety of plants usually grown especially in a flower or herb garden	an ornamental plant suitable for planting in a flowerbed