I have two words for you: Raised Beds. Tennessee clay just doesn't have the drainage that most of these plants will insist on.

I haven't had long term success with any of the plants you listed -- but I do want to say that I planted Walker's Low catmint last summer and it is doing great in clay **so far**. We'll see how it does through this year! I do also grow Agastache (hyssop), but I treat it as an annual. I even planted two types of Agastache in a tub last summer for extra drainage -- and it lived through the winter -- but the wet early spring still drowned it. :-(

Now, Gaillardia is native to TN and therefore adaptable, so you may have some reasonable luck. Good luck with whatever you try!

Thanks for the reply, amazondoc. I know what you mean about clay, having lived near the Cumberland Plateau most of my life. :-) I did lots of raised beds for my roses when I lived outside of Cookeville. The new bed does have a raised mound in the middle to raise the plants there even higher, although it may not show up well in the other photo I posted.

Where I live now, in Madison, we have brown loam soils over clay. I have about 8 to 12 inches of loam before we get to clayey subsoils. The utility company came through and trenched, so I got a good look at my soil, as shown in the photo below. No grey mottles to indicate poor drainage, although that may not be the case everywhere! And, of course, the ubiquitous clay is below that, but it is a little further down than what I've had before.

{{gwi:1280440}}

I've never lived anywhere that didn't have lots of clay before, but then I've also never lived anywhere that didn't have acid soil either. Not the case here in Madison. I guess being close to the Cumberland River and right on top of a layer of limestone makes a big difference. Water does seem to move fairly rapidly toward the river, which is about 100 feet below my elevation and about a mile away as the crow flies.

Anyone else trying these plants in my area?

In my experience (as a grower -- I've dealt with most of these plants in pots, which actually tends to make them rot out faster in wet weather than in the ground), Perovskia and Santolina demand excellent drainage. Also full sun. Nepetas do pretty well -- I've had success 'Walker's Low', 'Auslese' and 'Six Hills Giant' in containers and in slightly-amended-with-soil-conditioner-but-still-mostly-clay ground. I'm not familiar with that salvia, but can tell you that the salvias I have had success with were S. nemorosa 'May Night', which did OK, and S. transyvanica 'Blue Spires', which did great. The native/southwestern/Mexican salvias perform much better than the Euro species as a whole, IMO. Agastache x 'Blue Fortune' has done well for me, as has A. rupestris. Both are short lived perennials by nature, as is Gaillardia. They just do a couple-three years and out.

The cedar glades of the central TN basin are natural xeriscaping workshops, and offer plants with incredible drought tolerance. In July the center of a cedar glade resembles a mall parking lot, with waves of heat rippling up off the rock. In addition, these cedar glade plants are adapted to the seasonal flooding that occurs on those limestone pans in winter and spring. You might consider going native with some of your xeriscaping. I can give you a list of plants to seek if you're interested.

Marty

Hi, I am enjoying this thread.. I have grown Perovskia and nepeta, but both in raised beds.. I have never had luck with Santolina, I guess again the drainage wasn't good enough.. I would be really interested in the list of natives though if you could post it Marty.. I am wanting to rid my front yard of lawn eventually and I think xeriscaping (perhaps with natives) would be really good for that type of garden. Sorry this is getting off your subject, but that list would be helpful to us all maybe! Thanks! Jenn

"I've dealt with most of these plants in pots, which actually tends to make them rot out faster in wet weather than in the ground"

Hmmmm....ya really think so? This seems contrary to what I've read and seen advised -- and since I do a LOT of container gardening, I'd like to have a better idea of what's really happening!

Hi April,

Here is a website that can help you with some of the natives: Sunlight Gardens This page is a listing of their draught tolerant plants. Maybe it can give you some more ideas.

We have a small garden near the road that I guess would be considered xeriscape. Never started out with that intention. It's hot, sunny and poor soil, but raised bed. We have columbine, cone flower, sedums, penstomens, coreopsis, butterfly weed, baptisia, argeratum, heucheras, meadow rue and I am sure I am forgetting something.

I hope this helps and have fun filling your new beds!

Rebecca

Thanks for the offer, Marty. Please DO post that list--I'd love to go as native as possible going forward.

I already have a selection of yarrows, sedums, coneflower, lambs ears, daylillies (the old fashioned kind) and shasta daisies in this same area, and they seem to do well. But they are in the slightly higher portion (3 or 4 inches) of the garden. I think I will probably have to build my mound higher and broader to keep the ones that like dry soil from having wet feet in the winter and spring. I had planned to put the santolina on the mound, as well as the lavenders (which I've had good success with, elsewhere on my property). I had originally planned to put the Russian sage nearby, to offset the yellow of the santolina, but it is too big to put directly on the mound, so I think I will have to put it in the higher section of the garden and cross my fingers.

Thanks for the help, everyone.

"The problem with drainage issues in container gardening is due to the physics of water and gravity interplaying with the dynamics of plant growth. I'm no physicist, needless to say, but the situation has been simplistically explained to me thusly: Gravity, as we all know because we don't fly off into space, pulls everything toward the center of the planet. The bigger the mass, the more the gravitational pull."

Whoa there, that's a HUUUUUGE leap to make -- from gravity to container drainage!

"The water residing in the moist soil of a container (referred to as the water column) drains out faster in a big container than a smaller one, particularly if the plant isn't particularly well rooted out or growing vigorously, because there's a bigger mass of soil."

Errrrr.....In my neck of the woods, small containers nearly always dry out faster than large ones. There's a LOT more at work here than gravity.

Here's a real life example from my own yard, happening this very spring.

For several years I have had wild columbine and Malva sylvestris happily reseeding themselves all over my beds. They come back every year, scattered both in the ground and in the containers that sit all over my yard. HOWEVER -- this past year has been especially wet. And my yard has extremely poor drainage -- I routinely lose perennials that require good drainage. So, what happened this spring?? NO malva seedlings in the beds. NO columbine seedlings in the beds. Guess where the only columbine and malva seedlings have appeared this spring?? Yup, you guessed it -- in my containers!

There's a reason why rock garden and alpine plants are commonly grown in containers. And it ain't because those containers have BAD drainage. ;-)

If you happen to come across anything in *print* about containers and drainage, I'd really love to see it. Thanks for your explanation, even if I don't quite buy it!

Yeah, but what kind of soil was in those containers where the seedlings survived? Garden dirt? Or loose, fast-draining soilless mix? It's almost an apples-and-oranges comparison.

You're quite right about there being more than gravity at work. They say the other factor is the dynamics of plants interacting with the moist soil. Small containers will dry out fast if there are plants with decent root systems in them. In my line of work (propagator -- I deal with gazillions of little baby plants) the tricky part is before there's a good active root system working in the container. And I'm talking plug trays, little bitty containers. It is so easy to give them too much water and rot 'em out, because they stay too wet too long if you're not careful.

One time the nursery owner where I work decided to mix some compost into our standard potting mix, which made it incredibly heavy, IMO. The shrubs and trees were OK with it (they live in 3G, 7G and 15G containers), but the perennials in 4" and 1G containers started rotting out almost immediately. Actually, that event was what sparked my attending that particular seminar on container drainage. I've read the water column/gravity explanation (which I may have mangled somewhat -- I'm doing it from memory and it took some doing to get my head around it at the time) elsewhere, too. I'll see if I can find it.

Marty

Actually -- until this spring, most of my containers have been filled with a mix of compost/manure, bark, peat, sand, and occasionally moisture crystals. I didn't start using "potting mix" (or even anything like perlite or vermiculite!) til this spring. None of the containers with the seedlings have anything even vaguely resembling "loose, fast-draining soilless mix" -- and, yes, at least one of them (about 15-20 gallon pot with a red buckeye) is mostly lovely clay dirt. ;-)

Marty -- your gravity explanation doesn't even make scientific sense. Gallileo proved many hundreds of years ago that objects with large mass fall at the very same rate of speed as objects with small mass. Therefore, the mass of the water in a container can not possibly interact with gravity to affect the rate that the water drains from that container. Gravity just doesn't work that way.

All the rain this winter has been nice. My understanding of xeriscape gardening is to grow plants that are happy with the existing conditions of the area. I've been growing in GA for 15 years in clay with no additional water. The plants that I brought to the TN mountains this autumn are thriving. The hellebores bloomed, looked great, are fading now. The columbines are in full bloom. My Echinacea are leafing out along with the black eye susans.
The biggest thing for dryland growing for me is enough organic materials incorporated into the soil. This increases drainage & paradoxically promotes water retention at the same time.

We provide Xeriscapes in Middle Tn Nashville Area. We were recently featured in The City Paper about a Xeriscape I did. The Xeriscape in the picture is a Xeriscape Herb Garden. It combines Natural types of stone, a liner for weeds, and French Thyme, Purple Sage and Creeping Rosemary.
Xeriscapes should have natural stone and drought tolerant plantings. The link is a do it yourself xersicape page for homeowners who want to make one. www.landscapenashville.com

Here is a link that might be useful: Middle Tn Nashville Xeriscape Page