Why did the person who coined the phrase "Roses are red, violets are blue" chose violet which is purple instead of a flower that's blue?

Answer 1

It first appears in Spencer's "The Faerie Queene" (1590).

In a fresh fountaine, farre from all mens vew,

She bath'd her brest, the boyling heat t'allay;

She bath'd with roses red, and violets blew,

And all the sweetest flowres, that in the forrest grew.

Now...obviously "blew" rhymes with "vew"

but why did Spencer choose violets?

Why not any two-syllable blue flower?

After all: couldn't he have picked the name of some other two-syllable flower

that was actually blue

that is native to England

especially to English forests (as opposed to marshy areas)

and (to fit his rhyme)

it would have to have a sweet scent.

Options are actually relatively few. Actually blue flowers native to England that have two-syllable names:

iris

lungwort (for obvious reasons, not used)

That's it!

The iris is normally found in mountainous and arid regions.

I.e. NOT a forest flower.

So: apparently, Spencer was forced by his own rhyme to pick an English forest flower that was...blue-ish

and the rest is history.

Answer 2

Cadence.                                       

Answer 3

The shade of  "violet" or "purple" contains Blue; a Primary color.

Answer 4

Poetic licence.                             

Answer 5

some violets can actually be blue, like these