Compost! We have clay here and years of adding compost really helps. We buy it by the pick up load and it is cheap, under twenty five bucks. We buy it from the people who take in yard debris/sell bark dust. You might look into this. Even spreading it on the soil and not working it in does help a lot. It does work it's own way down into the soil. You can spread it now and plant in spring.

You might pot them into gallons for the winter. Use potting soil.

Ditto. Many of us plant Clematis in clay. I have not seen Miguel (one of this forum's experts) here for some time, but I believe he also uses this method: mulching with compost. This increases the earth worms' population. Gradually, the soil gets better. If you have weeds, check out the lazagna method in the Internet.
Dig holes as big as possible for now to loose it up for new roots. Put some compost around (not directly on vines). Your new babies should be fine :o) What a coincidence, I also ordered 16 Clemmies from CH...

Thanks for these responses! I don't think I can face potting up all those clemmies for the winter -- if I make the holes nice and big, work in *lots* of compost, and then plant them now, do you think they have a chance?

According to recent studies, ammending the soil with comost and other organic matter is not recommended because plants tend to stay within this hole and not grow their roots into surrounding area. Here is what I found in this article:

Unless adding a plant to an existing bed, don't cheat by just amending the soil removed from the planting hole, for the roots need to be encouraged to be developed beyond it. This is especially true when planting trees and shrubs. Many studies have shown that amending the soil only within the planting hole actually inhibits root development beyond it. The roots need to grow into the surrounding soil, and the sooner that happens, the faster and better the plant will become established.

Use compost as a mulch instead. The soil will improve the natural way - from top to bottom. In your zone I'd use a thick layer of mulch, at least for the first winter.

In addition to what alina is saying, it acts like a bathtub effect. The water will pool into the finer soil area & very slowly filter into the clay. You may end up with root rot because of it.

Another recent controversy is to till or not to till. What they are saying is by rototilling to loosen the dirt & adding compost is disturbing the soil structure & all the microorganisms in it. Takes several years to get the structure back in place. Believe it or not it's those microrganisms that makes the soil go round.

The advice you have been given is definitely the best...just keep adding all the good stuff on top, the earthworms do all the work for you.

What I do for natural organic material for free is collect leaves in fall. I put them in the center of my yard & take my lawn mower with the bagger on it & mulch them down into very small pieces & sprinkle them all over my garden beds. I kind of see it as helping ma nature along with decompistion & they don't blow away because they are so small.

What stands out here is that you have poor draining soil, which is a much bigger problem than the clay.

Considering that you live in Denver, you might not have much soil before you hit rock. Maybe the rock is in the shape of a basin. Do you know your area well?

Is your house built in a recently developed area or is it in an established area? The reason I am asking is if the house was just built, the soil will be very compacted from all the heavy machinery and that could be the cause for it not draining well.

Still, there are soils that don't drain well. Don't add gravel, it won't help. I agree in the top-down method for improving soil, but there are other things to consider. Such as... are you in a rainy period right now or has it been dry, yet water still pools in the holes you dig. If it is the latter, then you could be on top of an underground spring, buried creek or a very big concave rock.

Some good reading regarding the amending of soil in the link below.

Here is a link that might be useful: Never Amend a Planting Hole?

I garden in clay here in NC and find clay wonderful to garden in for the most part since it is high in minerals and the soil tends to hold water well. The downside is that if it dries out, it can be a bear to rewet to any significant depth. The solution is to add something to break up the clay such as pine bark soil conditioner to a degree and then mulch like crazy with whatever organic material you can get-grass clippings, bark, pine needles, etc. If you go overboard and amend the soil too much, the hole will be a swimming pool and plants will often die. If you can prepare a large bed for quite a few of your clematis to live in, then you can afford to go overboard with your amendments since a larger bed will drain better than a single hole. Another option if your soil is rocky or excessively claylike is to build raised beds and bring in good topsoil to fill the beds with.

I used a mixture of soil, bark fines (same as pine bark soil conditioner but faster to type), and compost to raised vegetable beds this year. The growth and fruit production has been amazing.

From that result, and from everything I have read, I was thinking about lifting and barerooting all the clematis that are in the same area, mixing in bark fines with the soil before replanting. None of the clematis in that area are doing as well as clematis in other areas.

I planted a few perennials this year mixing in bark fines with the soil first and I swear there has been less plant shock and good growth for first year plants. I also used it in containers. It holds moisture, yet the excess water drains out. I can't imagine planting without it.

I think the distinction is what type of clay. We moved into one of those typical suburban-sprawl neighborhoods where everything was clay and over the years (+20) of adding organic products (and not raking all the leaves from the surrouding trees) - our soil has improved. I have always tried to grow azaleas and rhodies in SW Chicago burbs, and just the last few years I had luck with them (I am not amatuer by the way - roses, orchids, limes grow well for me). It just came down to the soil. Recently, (last 5 years) I have been dividing more perennials more often, and the recipients cannot believe my soil in terms of texture. Some even asked if the plant was potted up for the summer. Compost really helps. Clematis don't like wet feet but in my experience they like lots of water; just well-draining soil - so dig a crater and ammend until you can't stand the sight of another bag of compost. Also, use plants that don't mind the clay until the more finicky types (azaleas, rhodies) would perform well in your bed. For example, I planted a long stretch of perennial border with hosts, now that other plants can grow there well - I am slowly taking out hostas and planting azaleas, tricytris (aka hardy Jap. orchid), heucheria, and some Japanesse maples, all of which would have succumbed in the crappy soil that was there 10 years ago.

Bradarmi, what do you mean it depends on the type of clay? You mentioned this and then didn't explain anything about what you meant and how the type of clay affects anything.

You also say dig a crater and amend as much as possible. If I did that in my area, I would create a swimming pool that would collect rain when it did fall and my clematis roots would rot. This might work great for water loving plants but not clematis which even you say don't like wet feet.

Well nckvilledudes, I think that here in Illinois, anyway, the clay isn't the problem so much as the suburban removal of topsoil. The forest preserve close to our house is logically the same clay with the topsoil intact. I think the common practice of removing the topsoil (especially in new subdivisions) makes things worse since there is no buffer between the clay and the "garden-able" soil that was there. That being said, I also remember reading/learning that there is "red clay" somewhere between Illinois/Indiana and the Atlantic Ocean, which although clay, is supposed to be a plesure to garden in - anyone from there have any comment?

Take chalk hill, chalk is usualy alkaine, (giving people the rather false impression clematis need alkaline soil) but the chalk just contains lots of water making clematis happy. I also remember that while most clay soil has a pH of >7, there are some places where the clay is acidic (I think for me it wasn't neceassarily the problem of clay, it was the problem of alkaline clay that resists water durring our summer droughts - which spelled disaster for my azaleas and rhodies.

Not sure about Aussie climate, is there a way you could raise them if the area collects rainwater? I think that even having the clematis wedged between 2-3 boulders might help (it works for my winter hardy cacti in Chicago winters). Does your rainfail coincide with a rainy season in summer with high temps or low temps? When clematis are actively growing here, they seem to love water in the summer, with temps consitantly over 80 and sometimes into mid-90's. Unless you live in or near a swamp, I wouldn't worry. I would be interested to hear about your conditions and I hope I didn't confuse you on the clay!!

Anyone have any ideas about other types of clay...acidic,red, etc.?

I can't agree with you more Bradarmi about the removal of topsoil over the subsoil being an integral component in the issue. It seems that when houses are constructed, the topsoil is dug away and then it is either sold off or redeposited in other areas of the yard when the soil is leveled. What you are commonly left with in most of the yard is subsoil with no topsoil. The topsoil is the biologically active portion of the soil with all the nutrients and microorganisms that contribute to soil fertility.

I also agree with your statement about alkaline soil and how it tends to hold deposits of moisture and that being how the idea that clematis need alkaline soil got started. (That and the fact that many of the British species were found growing in chalky soil). I have long ranted and raved on this forum about how clematis can grow quite nicely in acidic soil and how clematis don't need cool root runs but rather the moisture that is typically coincidental with cool soil. Been posting here on this forum for several years trying to get this myth dispelled.

Not sure if you think I am an Aussie or not based on your comment but I live in North Carolina, an area that has acidic clay soil and has historically been a farming state growing a wide variety of crops in the red acidic clay for many years. Our summers tend to be extremely hot, humid, and dry with the rainfall we get mostly coming from pop up thunderstorms which tend to be far and few between. The growing season starts early here and my 150+ clematis are at their prime in the early spring when temps are lower and the rainfall more plentiful. They also have a resurregence in the fall when the temps drop and rainfall is once again more plentiful.

LOL, nckvilledudes, I almost fell out of my chair reading the Aussie comment. I could have sworn my first born that your location read "Queensland". Maybe I didn't get my full pot of coffee this morning!!?

That same phenomenon occurs here (crater and swimming pool effect). By July, our summers are humid and hot, and sometimes the ground cracks. But once the first rain or two comes along, the water puddles and just sits there only to evaporate before it can do anything useful. (Hence the importance of mulch and organic material to bring it down into the subsoil instead of evaporating). So what do you do? Avoid low-lying areas, or does it even matter? Do you plant them a little higher (elevation not depth)?

No problem Bradarmi. You wouldn't believe the number of times I have been called Nick due to the username I use.

What I do is as I stated previously--amend the hole somewhat with pine bark soil conditioner to break up the clay and increase the ability of the soil to percolate somewhat better than it would otherwise. I also mulch continously with a wide assortment of organic material so that it can decompose and add to the tilth of the soil, to attract earthworms which add their castings to the soil and till in the organic material, and to maintain the soil moisture as well as it can. I also have most of my clematis either on drip irrigation or soaker hoses buried under the mulch to give them moisture as needed and to prevent evaporation of the water I do apply.

Here's a link to a good article about how to start a compost heap. It takes a few months to get the compost "cooking," so you'll have to use the commercial stuff until your first batch of compost is ready.

Here is a link that might be useful: Composting 101 et's Get Cookiing

The part I am questioning is how much nitrogen fertilizer you are using to compensate for the huge amounts of nitrogen that it takes to decompose the pine bark chips?

You shouldn't have to add anything additional nitrogen as the bark chips are aged. There might be a very slight loss of nitrogen, but it's so slight it shouldn't have any impact on your plants.

I made raised vegetables beds this year using 1/3 compost, 1/3 soil and 1/3 bark chips, aka bark fines or soil conditioner. Everything, tomatoes, peppers and herbs grew like crazy and I didn't add any additional fertilizer except for a half bag of potting soil split between three- 2 1/2 x 8 foot raised beds.

Steins is using bark fines in their premium grade potting soil. It drains better, but says moist longer, and it doesn't compact. I had to put a basil plant in the potting soil temporarily until I got the raised beds finished and it didn't sulk whatsoever- it just started growing strong.

I agree with Janet. So far I have never had to add any additional nitrogen above and beyond what is normally added when I fertilize and I tend to not go overboard with adding commercially available organic or inorganic nitrogen. Then again, I am always dumping more organic stuff like leaves, grass, compost, etc. stuff on top of the soil which in turn breaks down and makes nitrogen and increases tilth to the soil--just like Mother Nature does by allowing layers of organic material to pile up and naturally decompose to form the layer of topsoil.

I guess that makes sense if they are nearly decomposed to start with. The readings I have done on the nitrogen being lost even comes down to decomposing roots of a tree you have just taken down. I personally can attest to that one.

I do try to replicate ma nature as much as possible like nckvilledudes, just wasn't sure if it was enough.

Reading the thread linked below helped a lot, although he is still fertilizing.

Here is a link that might be useful: Tapla's explanation of pine bark soil conditioner

I live in Georgia where red clay is not only abundant, but comes in several types. Sandy clay is easily worked and drains well. Then there is the heavy clay that can also be worked, but the term chiseling rather than digging comes to mind. The dilemma when working with heavy clay is that the hole created becomes a bowl that holds water until it either evaporates or is taken up into the plant. Whether the back-filled soil is left as is or amended will not solve this problem entirely. Experience, however, has taught me that it is essential to add some amendment, for example, Nature's Helper, or a similar product of pine fines (just a couple handfuls or so per gallon of clay. Also, the hole should be no deeper than absolutely necessary, but of generous width, twice to three times the root ball or pot. Once the hole is dug, it should have grooves cut into the bottom and sides to try to encourage water absorption. Once the plant is set and the hole back-filled, a generous layer of shredded pine mulch, placed at least 6 inches from the plant's trunk and at least 2' out will over time help improve the soil, as well as offer immediate benefits. After all this explanation, I realize that I haven't shared what is probably the most important thing about working with heavy clay, which is to remember to never, ever try to work it when it is not absolutely dry. And I didn't mention the other type of clay, which is hard pan, and is a topic for another discussion.

I too, live in Georgia, and suffer by having bought a house in a new subdivision on a lot divested of its topsoil. I find this particularly ironic, as I bought the house specifically so that I could garden. As they say, live and learn!

Anyway, I'd like to recommend an excellent composting book, for those of you who desperately need topsoil and who have the time and space to make your own compost. The book is:

"The Complete Compost Gardening Guide: Banner Batches, Grow Heaps, Comforter Compost and Other Amazing Techniques for Saving Time and Money and Producing the Most Flavorful, Nutritious Vegetables Ever" by Barbara Pleasant & Deborah L. Martin (published in 2008 by Storey Publishing)

Don't let the long title daunt you or fool you - it says that it's for growing vegetables, but it's really a beautifully illustrated how-to-guide that's jam packed with everything you need to know about composting.

Happy gardening!

I'm new here. I have very heavy clay over hardpan. I tried many options before settling on my method. I dig a large hole, then continue at least a narrow section of the hole all the way through the hardpan. (Most of the digging requires a pickaxe.) I then fill this narrow lower section with gravel for drainage, and the planting hole above it with a combination of the native clay, compost,and sand. It's very labor intensive but it allows the plants to live.. A lot of my neighbors used a jackhammer to dig their entire yards and then amended the soil before attempting to plant. I don't think I could handle a jackhammer.

Swee-Pea, do you realize the conversation you posted on was from 2008?

RIP Miguel, you are very missed....

On the subject of amending or not amending, the clematis whose holes I dug up and heavily amended with compost have grown and thrived while those I just stuck into the native clay have mostly died off.....I don't care what research says (it is mostly on trees anyway) for Clematis, I will always advise to dig large holes and heavily amend them.

LOL. I didn't notice that it was from 2008. Thanks for the update on amending clay soil for clematis. It helps to know what has worked for others.