It may sound kinda weird but, I have mint and chives growing in My back yard. I usually use the mint and make a slight paste crushing the mint and some distilled water, this will not only give you a green tint to the soap but should also give you the smell as well. I have tried this with other projects and can not tell you what will exactly happen for soap making. But hey it may be worth the try.
Don't you find that it bleeds out? I was using it a lot, in the beginning, but I got so I couldn't stand that funky smells it leaves. The smell just dominates. Then, my soaps would bleed brown no matter how small of an amount I would use.