Since it looks like this thread is back to trying to make botanical sense out of the lyrics, then as noted some yrs back, if you accept that we're talking about wild roses and lily of the valley (not daylilies!), all below are common wildflowers or English ornamentals and of a size suitable for entwining in a girl's hair, too.

I'll entwine and co-mingle my raven black hair
With the roses so red and the lilies so fair
And the myrtle so bright with its emerald hue
The pale angelica and violets so blue.

(NB: ordinarily, you accent the second syllable of Angelica, but switch to the third and all is resolved.)

John Hempel