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radlew

Amending that 'ole Red clay soil-

radlew
18 years ago

Have a new garden that was all red clay in Kennesaw, GA. Landscaper amended it to about 1/3 soil conditioner. I want to plant Phlomis Russeliana which requires "well drained soil." Should I add sand? What ratio? Landscaper said to amend each plant hole as I aquire plants.

Comments (10)

  • matthewsdaddy
    18 years ago

    I don't know what a Phlomis Russeliana requires, but I will say this, my old house in Henry county had heavy red clay and my new one in Fayette has very sandy soil and I will take the clay anytime. You can lighten the clay easily enough, just mulch with wood chips and till them in every spring. Plants seem to reseed better in clay and hold nutrients longer too.

  • eddie_ga_7a
    18 years ago

    Exactly what was the "soil conditioner" pine bark? If your soil is now one third pine bark that should suffice unless you want to be a fanatic like me. Be careful with sand IF you use it: never mix it with wet clay because that is how bricks are created and never, never, ever use play sand (even though that is what the nursery is selling). Always use construction grade sand which should be available wherever they sell cement. Other amendments I use are perlite, pine bark mini-nuggets, and sphagnum peat moss. It wouldn't hurt to add a little lime though it's not technically a soil "amendment" and you can add just a touch of Epsom Salts but buy it at the drugstore where it is much cheaper than at the garden shop. Lastly, soak a few water polymers in water to allow them to expand and add this to the mix. I stockpile plastic grocery bags of this mix and save it for use on individual plantings. There are other things I add that are not soil amendments like Osmocote and alfalfa meal but you should be able to work out your own mixture. I don't worry about ratio and proportions much. Just remember that Epson Salts (magnesium) is a trace element therefore not a lot is needed. Think of it as putting salt and pepper on an egg: a little improves it, a lot ruins it. No matter what you plant, put a good mulch cover on it and water it in and you should be successful. Often drainage is improved by planting on a mound and when I say mound I don't mean fire ant mound, I mean pitchers mound.

  • rhizo_1 (North AL) zone 7
    18 years ago

    Organic amendments are always the cure for a clayey soil. Use as much as you can get your hands on. I like the soil conditioner ground bark stuff. Avoid sand like the plague as it will do nothing but create cement. That is quite a bad gardening myth. I'd advise you not to apply lime or any other mineral amendment without getting a soil test first. Do not add Epsom salts unless your soil test indicates that you have a deficiency of magnesium.

    If you have improved your planting bed with the organic matter, then please don't add any further amendments to the planting hole. That is ANOTHER bad gardening myth!! If you create a really great environment in that planting hole, the roots will be very slow to grow out into the surrounding landscape. This can create stunting, poor development, and all kinds of problems down the road. Many years of extensive research (why hasn't your landscaper heard of it?) has proved that all kinds of plants do better if planted into the existing soil as is, if planting hole by hole. You have already improved it by adding the conditioner.

    Believe me, as Matthew's daddy (above) said, red clay soil is NOT a bad thing. Even a little bit of organic amending goes a long way. I grow in very hard red clay, and am ceaslessly amazed at how easy it is. And GEORGIA red clay has the reputation of being some of the finest agricultural soil in the country, you lucky duck, you!

  • girlgroupgirl
    18 years ago

    The Phlomis isn't particularly wild about soil being super acidic. It naturally grows in Syria, in stoney outcrops. So it would prefer dry, rocky, limestone soil. If you have red clay, this is would be the opposite to the conditions in your garden.
    However, you can still grow it. I would NOT recommend simply ammending each "planting hole" as your landscaper suggested. It is far better to ammend a large growing area all at once. If you just ammend holes the first time around, then you have pockets of well draining soil right next to pockets of possibly soggy soil ( this is if you are gardening in clay, mind you). Also, the addition of pine bark mulch as your sole ammendment (if that's what was put in), can further acidify the soil.
    Your phlomis would do fantastically well for you if you dig (as in at least double dig) in LOTS, and I mean it takes LOTS of sharp builders sand. This sand contains copieous amounts of sharp and larger sand particles often with high limestone content that will leach into the soil. Another trick? Plant a hunk of old concrete right by your phlomis after you ammend the soil with other materials! This works with lavender, thymes and other limestone lovers too! Doesn't have to be a huge large piece either. Walkways, and sidewalk cement is a great thing to use. Also, planting your limestone loving plants by the curb also helps.
    A word of warning with phlomis. It also likes a lean soil, and our clay is nutritious. I would avoid ammending with copious amounts of manures, or compost alone. Mixed with the sand, this is great. But alone it helps hold in water AND break up soil particles. You want less water too.

    GGG

  • radlew
    Original Author
    18 years ago

    Thanks to all for advice. My Phlomis, which likes lean and dry soil, is not a lover of clay soil. So I think I will add some coarse sand and some perlite. The amendment, that my landscaper already added looked like it was heavy on the pine bark side.
    I already added some ground limestone last fall--good thing, since I CAN'T IMAGINE where I would find a chunk of side walk. But I'll keep looking!
    I also ordered some "water miser" from High Country Gardens. I'm surprised one of you said to add it to the Phlomis "hole". I had planned on using the polymers for "normal" plants. I am hoping not to have to put in a watering system...especially after the rain we had last summer....

  • jeffreyd
    18 years ago

    I posted a question some time back re: soil amendments in this clay we call soil. I was advised not to amend because it would discourage my shrubs from growing into the native soil. I guess that might make sense, but my bigger problem is this:

    One area of my yard is made up of almost 100% clay. I took some soil, put it in a jar of water, shook it, then let it settle. No humus, a little sand and 90% clay. I dug test holes, filled them with water and timed the drainage. It's now going on 48 hours and the water level has not dropped at all (except for evaporation). Looks like raised beds in half my yard.

    I rent, so I don't want to take three years out of my life to modify the soil. Where can I locate reasonably priced planting mix for raised beds? I'm in the Douglasville area.
    Jeff

  • woody_ga
    18 years ago

    AJC had an article in 2004 that listed 30 plants that do well in clay:

    1. Aster tartaricus
    2. Astilbe
    3. Bee balm, Monarda
    4. Black-eyed Susan, Rudbeckia
    5. Bugleweed, Ajuga reptans
    6. Butterfly bush, Buddleia davidii
    7. Canna
    8. Coreopsis
    9. Creeping phlox, Phlox subulata

    1. Crinum
    2. Daffodil, Narcissus
    3. Daylily, Hemerocallis
    4. Deutzia, Deutzia gracilis
    5. False indigo, Baptisia
    6. Flowering quince, Chaenomeles japonica
    7. Gaura
    8. Goatsbeard, Aruncus aethusifolius
    9. Joe-pye weed, Eupatorium
    10. Milkweed, Asclepias tuberosa
    11. Miscanthus, Miscanthus sinensis
    12. Miss Huff lantana, Lantana 'Miss Huff'
    13. Obedient plant, Physostegia virginiana
    14. Oxeye daisy, Heliopsis
    15. Purple coneflower, Echinacea purpurea
    16. Salvia
    17. Spirea, Spiraea
    18. Sunflower, Helianthus
    19. Swamp hibiscus, Hibiscus coccineus
    20. Winterberry, Ilex verticillata
    21. Witch hazel, Hamamelis vernalis
  • radlew
    Original Author
    18 years ago

    Thanks, Woody, for that list of clay loving plants. Of that list, I have already planted 2 Baptisia, 3 "Snowdrift" Astilbe, serveral black-eyed susans, 3 coneflowers. I may add an obedient plant--which is great for flower arrangements.
    Not from the list, are 3 Helleborus, 2 clematis, 1 confederate jessamine. Looking for ferns for shady side of house (how about Autumn fern?)
    And while I'm at it--is there a list of annuals that do well here in zone 7-b? Zinneas are my favorite. How about "Snow on the Mountain"--another favorite?
    When I lived in upstate NY, My Phlomis did well even 'though the soil was somewhat "clayey".
    Gee, I can't wait for Spring!

  • sugarhill
    18 years ago

    Radlew, I grow several autumn ferns. They like woodland conditions, so when I plant them (or most other ferns), I add 5 shovels' full of compost or leaf mold to the hole and dig it in. Every spring I mulch them with a shovel full of compost or leaf mold. Other than that, they are in the existing soil (I don't try to amend soil around tree roots). You want to try to recreate the soil conditions found on woodland floors, so I would give them plenty of organic matter. You have to think like the plant.
    The only time I never amend soil is when I'm planting shrubs or trees. I agree with the people who say amending the soil discourages growth into the surrounding soil.

  • camilles
    18 years ago

    I moved into my new home 1 1/2 years ago where the builder planted beautiful azaleas and other shrubs in the yard. But all they did was dig a hole in this hard, Georgia red clay and stick the shrub in there. After researching, I thought it would be a good idea to work in 1 to 2 inches of organic compost around the shrub to create a richer soil and attract earthworms. Now I'm wondering...was this a good idea?

    Thanks for any advice!

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