Alicia,
I've not grown perennial sweet pea my ownself, but, as to it's invasive tendency: It's growing across the street from my old farmhouse, circa 1929, on the site of the owner's mother's original house and garden. It's in a patch where originally planted way back yond, and holding it's own, but hasn't spread beyond it's untended wild holding.

They do ramble all around, so perhaps make a bed look a little unkempt, but , from what I see here, don't take over natives at all. Meaning, this bunch has been here for 70 years or so, and I don't see it straying too far. They are sweet, bright little flowers, and I enjoy visiting that "wild" patch to see how they are doing.

perennial sweet pea were the first seeds i planted here 10 yrs ago - and i'll second phylla's comments above ... my patch has never outgrown its original bounds. it rambles around on a 5' fence, but could easily use 10'. it's not fragrant, but i forgive that because it thrives under some fairly adverse conditions, i.e. drought, part-sun at best.

It definitely sounds worth a try, then. Thanks!

have been gone a while, but wanted to throw my 2 cents worth in. i've grown it for about 8 yrs now. it blooms on & off all summer. it does reseed some, so plan to pull out babies while small unless you let them get shaded out or deadhead. it gets a very deep, hard to remove taproot. if you have a trellis, and want it to go straight up you'll have to help it a little at first. it seems to prefer sprawling a bit, then climbs. it's especially pretty rambling down a hillside. it'll grow about 8'. the most common color is hot pink, but it also blooms in lavendar and white. i could probably ferret out a seedling come spring swap, if you'll be there. mine are all hot pink(to my chagrin). just let me know. phylla, are the ones in 'your' patch different colors? tam

I have a beautiful white one, still smallish, that I grew from a start off my Mother's plant. VERY drought tollerant.

I planted mine in full sun next to a barbed wire fence. I watered it just enough to get it started and pretty much have neglected it ever since. I worried the neighbor's cattle would eat it, but they never did. Not even the wild rabbits touch it. Very hardy. Even after all the cold weather we have had, it is still green.

They do well in any soil, but prefer poor soil. You have to help them get started climbing until they get a hold of their support. I have never known them to become invasive.
The prettiest clump I ever saw was growing up the guide wire of a telephone pole, with delicate lilac, pink and white flowers. There were yards and yards of Larkspurs of all colors growing around it.

Mother has hers growing on a white fan trellis with daylilies, roses and shasta daisies around it I think.

If you want the lovely sweet pea fragrance, maybe try planting some annual types by it.

~Annie