I have very hard, stiff red clay, but it drains very well. Horrified when I first moved here, I have come to be very grateful for it. Everything from turf to trees thrives with NO amendments whatsoever.

I do have an Osmanthus fragrans, a gift from my neighbor several years ago. It's not something that I would have purchased for myself because of the clay soil and knowing that my climate is borderline but it has astonished me.

We do not have an irrigation system which is probably the reason why it and my other woody trees and shrubs have done so well. Clay soils can stay saturated if irrigated regularly, frequently.

Our fragrant tea olive was given to us as a small three-gallon plant in 2006 and grew to a very robust ten feet tall in spite of some freeze damage three or four times.

We had to remove it this fall, sad to say. It was in the middle of our soon to be expanded patio area. It had become so wide and the trunk so large that a chain saw was required, followed by a stump grinder.

The Seattle arboretum used to have a small grouping of these that had become well above head height when I went and looked at them. The planting site was a comparatively narrow, sloping bed with a clay soil that at the time of year I went among them was so wet I could hardly remain in place long enough to read the tags - which indicated they had been there many years.

These had a firm, dark leaf that was not like what forms on the market and in mass plantings made on the University of Washington campus since have. These latter are quite apparently hot climate types not well adapted to our conditions, with the campus plantings having lost all the most recent growth to frost one time I was looking at them.

The one arboretum version may be a wild collection from a higher altitude or otherwise differ from the usually seen stock in some significant way. I should search the Botanic Gardens web site for a listing of it. Since the Center for Urban Horticulture was founded and the arboretum Visitor Center built, the staff compound worked on the bed where these were located may have become no longer publicly accessible - I don't remember.

The first location dating from 1975 would be the one I mentioned. So all or part of this planting survived the 1990 winter - coldest in 30 years - in some kind of viable condition on a greasy clay soil because it is still listed.

http://depts.washington.edu/uwbg/gardens/BGBase.php?txtSearch=osmanthus+fragrans&submitedits=&_submit_check=1

Thanks for the insights everyone. The water drained in about 5-6 hours in the second test and as far as I can read that means it's good enough drainage. But i'm finding various opinions on the amendments. It was recommended by the college kid at the nursery.

"But i'm finding various opinions on the amendments. It was recommended by the college kid at the nursery."

I feel like I missed a post because you haven't told us what amendment this is yet? Anyhow, you see Osmanthus throughout the south on clay soil and they are fine. I wouldn't plant one in the bottom of a ditch but other than that you should be ok.

Nurseries want to sell as much as possible to their customers so people should take advice to buy fertilizer or amendments or "supplements" with their plants, with a huge grain of salt. Wholesalers optimally fertilize plants to get them to that stage of production where they are sold. In fact many nursery plants in the US already have surplus fertilizer beads in the potting mix. In most areas of the country, it is absolutely not necessary to amend, fertilizer or supplement the soil where such plants are planted. Or to 'improve' the soil used to plant them! And is in fact detrimental to do so. There are a few known exceptions like palms in Florida's notorious nutrient poor soils. In that case rely on the advice of local extension offices, not kids at the nursery.

" The planting site was a comparatively narrow, sloping bed with a clay
soil that at the time of year I went among them was so wet I could
hardly remain in place long enough to read the tags - which indicated
they had been there many years."

"in some kind of viable condition on a greasy clay soil because it is still listed."

NB though that the difference between mucky clay soil in the PNW and the US SE is that in the US SE that soil will become water saturated in the middle of summer at times when air temps and consequently soil temps are ridiculously high. In the PNW nights are almost always < 60F, and there are not huge downpours in the middle of summer...and in fact very little rain for the most part at that time of year.

Thus with various standard landscape plants, especially BLEs, a site you could get away with for a plant in the PNW might not work in the US SE. At Greer Garden and elsewhere I saw rhododendrons planted in what looked like low spots where they would probably get summer root rot in my garden. Not quite at the bottom of swales but close.

That being said Osmanthus are clearly not especially root rot sensitive because again, you see them all over the south on clay soil...whereas you don't see standard lepidote rhodies at all.

Just something worth mentioning though.

It is just a bag of Pete's potting soil mix.

My clay is so thick that I figured I needed some but I'm not experienced.

I didn't think an amendment could hurt a plant but was more of a question of necessity. How is it detrimental so I can learn for next time?

Thanks for all the help and I think I'll be planting the OF this week.

Al

Nope, no, and not.

There's just no reason to add potting soil to the hole. This has been thoroughly debunked and I was probably a bit of a "hole amender" when I was a kid - I've been into gardening since I was 12 - but I now realize that it's totally unnecessary and usually counter-productive. You want the plant's roots to "break out" into the surrounding soil, as they "look for" moisture and food. Not "spoon feed" them everything they want, right IN the hole. Does that make sense? I have a Osmanthus x fortunei (child of O. fragrans) in an incredibly tough spot, south facing slope between 2 giant tree trunks, I think I only watered it once or twice after planting. No amendment of the soil which was clayish loam. It's done just fine. They have very strong root systems and don't need your "help".

Use the potting soil for pots!

BTW though it is a good idea to mulch, especially in the south to help prevent the soil from drying out and reducing your watering requirements.

potting soil is made to hold water ... your clay already does that.. so what would be the point of adding more water holding capacity .. bingo on the goal of profit for the nursery ...as the reason ... for the suggestion ....

now that you know how water moves in your soil ... the trick is learning how to water the plant.. none of this drink everyday nonsense ...

plant..water it in.. and dont water it again.. until the soil starts drying 2 or 3 inches down.. most of us.. could stick a finger in and find out.. you may need a hand trowel to find out.. both in the root mass planted... and in the surrounding soil .... we cant really tell you how it all works in your soil ....but dont be surprised.. if it might not be a month.. before it needs more water ....

the worse thing is killing them with too much loves.. watering at will with no insight into what the plant needs ...

i hope you read the link i gave above ... about planting high in clay soil ...

planting on a hill is problematic.. i believe it was covered at the link below ...

ken

http://forums.gardenweb.com/discussions/1827881/how-to-transpalnt-a-conifer-tree-huge-pix-post

also look at this one:

http://forums2.gardenweb.com/discussions/1590857/newbies-dealing-with-heavy-clay-soil

Ok thanks everybody. I did look at the original links. These 5 I'm planting are on a very gentle slope and the OF will be inside a fence and I've given them 3-4' of room from the fence and about 5' between plant centers. Filtered sun gets through much of the day but in winter full sun. For comparison I have a carolina climbing jasmine right in the same area that is thriving but a climbing hydrangea didn't make it.

Al

Climbing hydrangea come from rainy, semi-mountainous parts of China and although you do see big ones in the south, I have found them tricky to get established. Somewhat like Stewartia in that regard. They really 'want' to have consistent summer monsoon-like rains with rather cloudy days, too...which is what happens in Asia but not here.

OTOH some Asian plants like Pittosporum and Osmanthus are tougher. At Duke Gardens, I spotted some Osmanthus naturally regenerating, as they do in my garden. In Barcelona, I saw what l'm pretty sure were unwatered Pittosporum tobira. Huge ones. (Barcelona though, not nearly as dry as Southern California, though some people would assume their climates are quite similar)

The problem with amending planting hole back-fill when planting in damp clay soils is this changing of the soil texture inside the planting hole may cause it to collect water, like a sump.

There is never an occasion - whether it is a clay soil, sandy soil or in between - where the problem with amending back-fill is this causing the plant to "like" the amended area better, not grow as readily into surrounding soil as it would if there had been no amending. Roots are geotropic and always grow as quickly and as vigorously as possible away from the center of the plant and into fresh ground, whenever the plant is in good enough health to accomplish this. Failure of plants to root promptly across amended zones and into unmodified soil around them is due to plants being in poor condition at planting, or in being stunted by the often adverse moisture conditions created within the planting hole by amending. Anytime enough amendments have been used to significantly alter the texture of the planting hole back-fill - which is the main reason for doing it - how water moves into, through and out of the amended hole is liable to be affected in an undesirable way.

Casual observers not conducting organized trials using controls may also conclude erroneously that amending of planting hole back-fill (or small beds) has produced an improved response because typically once newly planted stock manages to get out of amended holes and root into the natural soil beyond them it takes off. Clearly demonstrating that the thing to do was to plant with the roots in direct contact with the existing, non-amended soil in the first place.

As usual I'm not sure what you're arguing with.

Or why. LOL

extension.arizona.edu/pubs/az13592h.pdf

More than 30 studies conducted on a wide variety of soil types found that in most cases organic amendments in the backfill reduced root and shoot growth. Several reasons can cause this reduction in growth. When backfill is amended with organic material, decomposition occurs, the plant settles and the root collar will sink below the soil surface. Adding amendments to the soil creates an additional interface between the organic potting media and the mineral soil. Roots may stay within the amended soil and grow not into the native soil, creating a root bound plant within the amended soil.

" changing of the soil texture inside the planting hole may cause it to collect water, like a sump."

And I suspect this is related to why the BAD advice of hole amending became popular at all. In climates with hot summers and highly irregular, sometimes scant rainfall (i.e., not the PNW, where your rainfall or seasonal lack of is more predicable and therefore irrigation for some kinds of plant is the norm, not the exception)...it's possible that a moisture retentive patch of soil superficially makes plants apparently easier to water. And therefore "easier to grow". Say you plant 10 Gumpo Azaleas in hard southern clay, and minimally mulch them. For 5 of them you do the "5 gallon hole for a 1 gallon plant" thing and backfill with moisture retentive compost/peat/perlite mixes. For 5 you plant straight in the brick clay.

Let's say you have a big, quick downpour on June 1, getting 1/2" of rain in 10-15 minutes. As can definitely happen in the eastern 1/2 of the country. Most of the rain near the straight-hole plants will run off. In the "sumps", a lot of the rain will manage to be collected because the potting soil mix will percolate better. I can totally imagine that 2 weeks later, w/o supplemental watering, the 5 plants in the "5 gallon holes" are still going to be green and perky, and the straight planted ones wilting. But it's a devil's bargain for all the reasons mentioned in the paper I posted.

In fact like anyone I can't really get into my head 25 years ago, but I definitely remember READING the advice to amend/backfill, but I think after a while I instinctively started avoiding it, because I realized it caused such problems. In my late teens I rototilled an entire bed adding Permatil, which suddenly made it possible (or at least somewhat more possible) to cultivate the various high elevation South African forbs I was into at the time. But entire bed amendment is very different from in-hole amendment; and golf course/athletic field managers wouldn't pay hundreds of thousands to do whole field/whole course amendment with say, Turface, if it didn't have a positive, provable outcome...with growing grass. (may not help typical trees/shrubs nearly as much...they have bigger, stronger roots) It was a hassle to get the rototiller and clearly I realized running around putting permatil into individuals holes wasn't helping or wasn't going to.

BTW I was at a nursery somewhere recently, honestly can't remember where, and heard this advice (amend/backfill) dutifully recommended. So the idiocy is still out there. (as happened to the OP, too)

In fairness to embo - because I am clearly the fair one - he's probably right that the sump effect is the main problem. But as I'm pointing out, and the authors of the paper believe, the sump effect itself perturbs the optimal growth pattern for the roots.

Yes, again your response does not apply specifically to what I said (about what happens in amended planting holes). So there is no point in continuing, as you will just keep it going around and around, if you can. The validity of what I posted already is actual, which is good enough.

"Yes, again your response does not apply specifically to what I said (about what happens in amended planting holes)."

Again, you exhibit curious reading comprehension problems. It's as though your brain blots out any contradictory evidence or something. Which is fine, I have no personal ill-will towards this, I just want the body of knowledge at gardenweb to be complete. I'm clearly not pursuing some kind of vendetta against you as you do against me. I've never disparaged your posts as being useless, and in fact have up-voted many of them.