Some folks feel that planting in native soil teaches a plants roots to go looking for moisture and nutrients rather than having it handed to them. It causes them to search deep and wide and this renders them more able to withstand difficult conditions like drought.
If you ammend a planting hole in compacted soil you are virtually teaching a plant to feed within the ammended portion, as venturing out through the compaction is way too difficult. So the roots grow round and round and you end up with a plant with no sense of looking out for itself so to speak.

Breaking up the sides of a planting hole is always recommended- you want it to be easy for those roots to go exploring. Whether or not you ammend in addition to that depends on where you fall in your thinking. If I do ammend it is very little, and always with substances that enrich the biodiversity in the soil and improve tilth- not just "fertilizer".

Composted manure and peat can be good if your soil and the plant going in need it.
IMO it is a YMMV sort of thing.

Most important on az and rhodo's are good drainage. If water puddles in area after rain, it's not draining. Raised beds only option in such an area if must have az and rhodos.

Here is a link that might be useful: here's more good info

Despite the advice not to amend, I'd have to say that I do amend some but am careful not to overdo it. The worst extreme is the person that takes ALL the soil out of a hole and replaces it ALL with purchased topsoil, or compost or something.

I sometimes come across truly awful spots in my soil, especially where the previous guy put in a pool and left crappy soil mixed with I don't know what else - this is clearly soil that could become a set of crockery if I had a kiln.

When I do amend, it is for the purpose of adding organic matter (in the hopes of attracting worms I throw a pile of leaves at the bottom of the hole) and I am careful to thoroughly mix it with the native soil before adding anything back in to the hole.

And ditto to what paula said about azaleas. Around here, I raise them up a bit to improve the drainage. Then well mulch them to keep the moisture in and the roots cool.

I didn't know you guys in Wisconsin had clay soil ... I thought it was all down in Georgia!!

The main problem is creating a situation where the movement of water into and out of the planting hole is altered. During dry conditions amended planting holes may shed water excessively to unamended soil around the planting hole. Amended planting holes dug out of damp claylike soils may receive water from the surrounding soil during wet conditions and collect it under or around the new plants.

Peat, bark, sand... these all make the backfill more coarse than it was before they were added. So the backfill has a different texture than the surrounding unmodified soil. This is what causes problems.

Likewise coarse potting soils often produce problems for new plants when rootballs grown in these are left intact during planting.

Anthropomorphic concepts like roots "choosing" to stay in "better" amended backfill or reaching the supposedly nasty natural soil outside the amended hole and turning back, like retreating armies are not based in what actually goes on. Specimens healthy before planting tend to grow more vigorously after rooting outside of the amended hole and into the unamended soil around it than when still growing across the amended area. Since this often occurs within a year after planting, the false impression is given that the amended backfill was helpful - the trees or shrubs took off relatively soon after planting.

Especially with clay soils, amending individual planting holes can easily result in planting "buckets" that retain excessive moisture because of the slower draining clay - the bathtub effect. Research has also indicated that introducing a soil mix of different texture - i.e. any type of amendment - into a planting hole creates interface issues and can slow drainage in even very well draining soils as well as potentially retarding the expansion of the root system into the unamended soil. If you must amend, amend a large area - well beyond what a typical root system of the plant in question would achieve, like an entire planting bed. You can see where this can get problematic when one is planting trees :-))

Otherwise, with clay soils it is better to dig very wide, shallowly dished planting holes or create raised "mini berms" to encourage good drainage. Backfill only with the soil removed from the hole and use any amendments as a mulch or top dressing around the plant.

just a general rule.. always exceptions.. what works best in your yard.. is for you to experiment and find out...

as noted.. the extreme replacement of all native soil is not good ...

now we are talking... trees/shrubs/conifers [i will use 'trees' generically] .... not annuals and perennials nor veggies .. which are an animal in themselves .. different rules ...

think forests.. no one amends soil.. no one waters.. no one fertilized... and forests regenerate themselves across the globe ...

water management for trees .... is the only issue ... excepting the swamp plants .... trees do NOT like to stand in water .... in nature they rely on rain ... a big dump once a month or once a summer.. then dry roots as the water moves through the soil structure .... ergo .. adding anything to the hole.. that retains water is a negative.... bearing in mind.. a LITTLE of this or that is going to hurt ....

of all my conifer friends ... that have to deal with clay ... they plant half the roots in the clay .... and half in a mound above the clay with decent soil [you dont want to install a clay cap on your mound so this is where you might add something to not allow the cap to form] ... that way .... the tree has both water.. and air .. and the tree can eventually find its way into the clay ...

i am at the opposite extreme of the soil dynamic.. pure yellow mineral sand ... when i moved.. i had 1500 potted hosta.... had the giant beds tilled to 12 inches... and took the potted wad of peat based potting soil with the plant.. and stuck them into the sand .... over the years i have lost hundreds of hosta.. because... the sand.. wicks all the water out of the peat .. and once peat drys.. there is no rewetting it.. in mother earth ... the hosta eventually dry rot.. unless i spot the problem before they expire ... big hosta grew right out of the stuff.. but smaller hosta... struggled.. hence i learned that overly amended soil .. diverse from the native soil structure.. can be more problematic than good ...

we are in the shrub forum.. so lets talk specifically about shrubs.. which, again.. are no different than trees and conifers .... since i moved out into the country ... i drive around all these farms.. where you see.. out in the middle of a field.. a grouping of trees and shrubs.. that have been there for 100 years... the house is gone.. but the drive and the trees are still there.. no one is feeding them.. no one is watering them ... and some of these lilacs are bigger than my house .... so i am leery to suggest that 'trees' need anything more than some water at planting and the first year ... and in drought the second year ... beyond that ... they can take care of themselves ...

too often.. the homeowner.. if told one teaspoon of whatever is good.. will throw in a handful ... and then.. what the heck.. why not 2 handfuls.. then complain that things are so hard to grow .... i sum up this logic with the statement.. do NOT kill them with too much love ...

dig hole.. or mound in clay .. insert plant.. PROPERLY WATER for year one... insert finger to determine if water is necessary ... many posts about that ... and offer water the second year if drought.. mulch well [if suggested on clay] .... and walk away ... do NOT overthink trees ...

any better???

ken

PS: always to to local nursery peeps ... and ask how they do it ... now that you have the basic idea.. you can have a conversation with them .. they are better equipped to discuss planting in your region .... but if they suggest you need to buy soil amendments... then they are not worthy ...

When you put it that way, it's all perfectly logical. LOL

I'm pleased to say that I actually did it right with regard to amending the soil - where I did do it (my Azalea), I made a point to mix the original soil in with the peat moss, and made sure not to add too much peat moss to the mixture.

At least that's one thing I don't have to add to my ongoing "duh" list. Seemingly not learning the first time around...I just poured what was left in my miracle gro bottle (with particles and all) into my lovely hanging baskets and ferns, and now they're all browning.

I don't know what's worse, the fact that I did it or the fact that my husband watched me do it and never said anything (he says now he was wondering why I was doing this knowing it wasn't going to be a good outcome). ???

Two years ago, I decided my hostas needed a good dose of fertilizer...read the recommended dosage but figured more is better, so each hosta got at least 1/2 cup of fertilizer and turned to a crisp a week later. Crabby neighbor next door, old retired guy, was so peeved because "he has to look at it" --- as if I didn't think my mistake was dumb enough but then I have to hear it from my neighbor (they ARE my hostas on MY property, no less).

I've been so paranoid about fertilizing (veering off subject here), that I have only miracle growed once this year, and the one time I did I ruined my plants!

I've been reading about how you shouldn't fertilize the first year (I planted a lot of clems and perennials this year), and not to fertilize before they flower, etc., etc., and I'm having trouble keeping it all straight so I decided not to fertilize at all. Last year, everything got miracle grow once weekly (though I didn't have as many plants either).

I appreciate all the feedback - I'd be spending half my time at the library and/or nursery if I didn't have this forum. I'm off to plant my Rhododendron.

The same common reason for adding soil amendments - altering the texture - is the same basis for possible problems. Adding too little to change the texture accomplishes little, adding enough may create water movement and retention problems.

Small plants like alpines and annual flowers and vegetables can easily have their whole rooting area modified. And new amendments can be added as needed. It is a different matter with trees and shrubs with large root systems and long spans in the same location.

Successful fertilizing requires the right formula in the right amount at the right times. Sample your soil and have it analyzed for some insight into your soil conditions. Ask your state Cooperative Extension for assistance with this.

Fertilize with the right stuff in the right amount. If a newly planted specimen is being subjected to a limiting nutrient deficiency withholding appropriate fertilizer because the plant is newly installed accomplishes nothing useful.

According to soil tests, the soil in this area of NC and SC is very deficient in Phosphorous - I therefor mix either a small amount of triple phosphate or a slightly larger amount of soft phosphate - which ever I am able to find when I run out - into the back-fill soil of a planting hole. Other than that, I add compost and/or alfalfa meal as a thin layer under the mulch, so it works its way down into the soil over time. The mulch gets replenished and the ring widened - usually annually - so the top layer of soil does improve over time. I am very tempted at times to massively amend my hard red clay, but I neither have the time, energy, nor the money. As implicit above, I do amend my vegetable and flower beds, so whatever shrubs go with the flowerbeds do get the benefit of that. They grow better, but I am not sure how much of that is the better soil and how much is the more water demanded by the flowers.

dibs is spot on with suggesting a soil test... knowing if your soil is actually deficient in some requisite thingee [scientific term] is a great starting point ...

that said ... IF YOU BUILD YOUR SOIL .... you almost never need to feed your plants ...

so you need to learn how to build a good soil ... and that would start with adding compost every year ... think spreading manure on a production field ...

today.. almost every city offers free compost ... we know it as BLACK GOLD ...

if you were to simply add 2 or 3 inches to entire beds every spring or fall as a top dressing .... in a decade.. you would have super soil ... the worms and soil dynamics will take care of incorporating it all ... and every time you dig.. you will do such ....

or put it on.. and get a good 3 tine pitchfork .. and just loosen the soil... then put it on ...

gardening.. frankly .. is more about good exercise.. rather than how much money you can spend on snake oil remedies... if there is a product that serves a purpose.. there is most likely an organic way to do it.. that just requires some hard work ...

learn about composting your garden ... and you will be much further ahead... esteropal over in the hosta forum is a compost nut... many posts over there about the stuff.. and its uses ... you may have to search them out ...

btw .. rhodies and azalia have shallow fibrous root mats.. that should never dry ... some good mulch to keep the mat cool and damp.. will get you further ahead rather than the amending .... but dont use peat moss.. as it can become water repellent as a top dressing .... and mind you.. nothing deep ... roots need air as much as water ...

ken

So, if I have an area I plan to plant next year, should I start composting it now?

Yes.

Hard way: scrape sod up, turn over soil, add amendments, let it sit til next spring. Then til it all together, plant, mulch. Add compost yearly..my favorite way via chopped leaves mulch.

Easy way: Get all the newspaper you can find. Cover area with well overlapping sections (6-7 pages thick). Paper a little wet is better, dry will blow away as you're working. Put your amendments on top, the thicker the better; chopped leaves, mushroom soil, purchased compost, chopped grass, heap it on to about 18" high. From now til next spring, it will all rot, worms will start to drag compost into the soil. If unsightlyness is an issue, you can cover it all with a light layer of purchased mulch, and this will also weight it down. Next spring you will be able to just dig in the bed and plant. It usually takes about a year for all the newspaper to rot, but depending on how much moisture you have over the next year, you may have some persisting. No matter, discard it, it will have accomplished the job of killing the weeds and grass. Add the yearly compost as above.

Bed building is big work, either way, so stages may be practical.

easier way ...

lay hose in form that pleases you ... spray with roundup .. and immediately start obtaining compost ... place directly on top of dying grass...

by next spring.. you will be able to sink you arm to your elbow ... in my sand anyway ...

then in fall.. collect and mow all the neighbors leaves.. and throw them on top ... smaller leaf size cuts down on them blowing away ..

i always have next years bed in progress.. the year before ...

ken

and learn the difference between compost and mulch ...

maybe a new post ...

ken

Yes: The natural system is for rubbish to fall on the ground and be processed there, near the surface, where most of the air is. This is emulated in gardening with mulching and top-dressing.

There doesn't have to be a difference :-) Mulch is simply defined as a top dressing to the soil - it can be organic (bark, leaves, grass clippings, compost, pine straw) or inorganic (sand, gravel, shells, lava rock, recycled tires). Compost makes an excellent mulch - perhaps the best of the organic choices - but is generally not readily available in the quantities most folks need unless obtained from a commercial composting facility.

The only mulch I use in my garden is compost. Have for years and have not needed to offer supplemental fertilization since. I also have suberb loose, well draining yet moisture retentive, organically rich soil.

There is no sod. The areas I am considering are wooded. In some cases these are permanently (practically) covered in leaves, and in some cases are bare soil and/or lilies of the valley. The soil in a good part of it (leaf-covered or not) tends to be somewhat hard and medium-heavy clay. Where I have done some test planting this year, I did amend the immediate soil, and the plants seem to be doing well, notwithstanding proximity to mature maples,but left alone not much grows.

NEVER amend under a maple.... guess where the maple will grow roots???

mulch goes on top ..

compost goes on top.. or is incorporated ...

e.g. hardwood chips are a great mulch .. hardwood chips incorporated... will steal nitro in the process of breaking down ...

my point.. for a newbie.. is that words mean things.. and two words are not used for the same thing ...

ken