Yes, I think this must be right.

The best version of Wildwood Flower I have ever heard, even after all these years, was released by Joan Baez on, I believe, her very first vinyl, which I think was then titled eponymously, but is now usually known as "Joan Baez - Volume 1", there is an equally good companion album "Volume 2". Thank heavens for minor miracles, these were released on CD in 1987 unmucked about by ignorant modern audio engineers. The result is that these two, to me priceless, albums still sound as fresh as when first released in the 60s. Other wonderful tracks are "Fare Thee Well" aka "Ten Thousand Miles" - so much better a rendition than the dirge version of the song popularised by Nic Jones (I'm a fan of Nic's, but IMHO that was one of his least successful renditions) - "Donna, Donna", "Little Moses", "Wagoner's Lad", "Engine 143", "Lonesome Road", "Banks Of The Ohio", "Pal Of Mine", etc.


I also have the Joan Baez song book, which gives the lyrics to Wildwood Flower the same as that handed down by the Carter Family:

1
I will twine with my mingles of raven black hair,
With the roses so red and the lily so fair,
The myrtle so bright with its emerald hue,
And the and the leader and eyes look so blue.

2
I will dance, I will sing and my life shall be gay,
I will charm every heart, in its crown I will sway.
I woke from my dream and all idols was clay,
And all portions of lovin' had all flown away.

3
He taught me to love him and promised to love
And cherish me over all other above,
My poor heart is wondering, no misery can tell,
He left me no warning, no words of farewell.

4
He taught me to love him and called me his flower,
That was blooming to cheer him through life's weary hour,
How I long to see him and regret the dark hour,
He's gone and neglected his frail wildwood flower.

It is clear that the meaning of the first verse has been mangled almost beyond recognition by the oral tradition, but some time ago, before the age of the www, I reckoned that with applied intelligence one could retrieve most of it. The girl is singing about putting flowers in her hair, and the rest of the verse seems to be describing the flowers. This makes it clear that the "With" at the beginning of second line probably wasn't originally there, and the that the last line was misheard, and sticking as closely as possible to the sound of the currently accepted version, was most probably originally something like:

And the pale oleander and lilac so blue.

This would have given ...

I will twine with my mingles of raven black hair,
The roses so red, and the lily so fair,
The myrtle so bright with its emerald hue,
And the pale oleander, and lilac so blue.

... which, besides now making perfect sense, is a really pretty lyric.

However, there are problems with this interpretation.

The first I discovered even back then is that oleander is a herb from the Levant. When it first came to be grown in gardens of North America, I have no idea, but it's possible that it was sufficiently widespread to have appeared in songs of about the vintage of Wildwood Flower.

Then later, with the advent of the most complete library in the world, the www, I too discovered the same source that you appear to have found, and quite a few other others, and, which rather galled me, none mentioned even the lilac, let alone the oleander:

This appears to be the original penned lyric:
And the pale aronatus with eyes of bright blue.

I'll twine 'mid the ringlets of my raven black hair
The lilies so pale and the roses so fair
The myrtle so bright with an emerald hue
And the pale aronatus with eyes of bright blue.

This is yet another version different from both the original and the Carter family's.
The pale emanita and hyssop so blue
www.mudcat.org/@displaysong.cfm?SongID%3D2957

So, you can either go with the original penned lyric, aronatus, or the one of the other versions, but I would recommend at least correcting the Carter Family version to make sense.