swales as sunken beds idea

Hi guys! I am a newbie here so I hope some of you more experienced permies can help me out. I was wondering what you think of my idea I had recently of using swales as sunken beds instead of just mulch filled paths.

I live in an area where it can get very dry (think drought) and was researching sunken beds when it dawned on me that swales are essentially sunken beds. The hills behind my swales tend to dry out quickly due to the south Georgia heat so I thought, why not plant the swales with flood resistant plants such as willow (or many others) and plant the hills with drought resistant plants such as lavender and thyme, to name a few. The swale would still be mulched around the plants and the hill would also be mulched.

I mean would it work without compromising the role of the swale? Is there anyone else who actually plants in the swale?

I can't say I've done that but it seems to me that it would work in your situation. I say this because last winter, I had no drain in my house and so I dumped all my dishwater (including tomato seeds) in a spot outside my front door. When the snow started thawing, we dug a trench to divert runoff which was sort of like a swale in one spot (although drainage was the idea).

The soil was subsoil that was there from our home excavation (we'd just built and finished building the previous November), we had already removed the topsoil to dig down - nothing grew in it that springtime EXCEPT I had some tomatoes sprouting up inside the diversion trench. They survived without being watered for most of the summer, in horrible soil that grew nothing else except in that trench. Not that they got big (and we eventually did grading in the area, which killed them) but they survived and they aren't drought resistant plants. I think because when it DID rain, the water accumulated right where they were. I also wonder if the trench provided shade for them as well.

So it seems to me that if you intentionally did this using drought resistant plants, it would work. If you position a swale correctly to hold water instead of divert it like our trench was, I think it would work unless those times of being soaked would be bad for those particular plants. I believe that's why the usual idea is to plant on the downhill side, so the plants aren't sitting in water when there's a lot of rainfall.

That's why I thought some plants such as willow and elderberry would be good inside the swale perhaps. They can take flood conditions but do well when water is moderate as well. I posted an example of the idea at http://tldeliberately.blogspot.com/2015/02/swales-as-sunken-beds-idea.html , if you would like to look to get more of an idea of what I mean. Thank you for your comment.