I don't amend and I doubly especially wouldn't amend a rock garden. Most alpine/rock garden favorites like a lean soil. In my own rock garden I bought lots of varieties, gave it a year or so, then bought more of what did really well and didn't worry about what did not thrive. It's so hard to weed due to both the slope and the rocks that I just want it filled in and colorful.

gravel, not sand.

NJ has a clay based soil. I would definitely add gravel. Heruga's the guy who was covering his perennials with tarps last winter to keep them dry.

in all my years.. i never dug a 3 foot hole.. to amend soil .... [your intended depth ....]

when i dabbled in alpines ... i had a yard of scree delivered to the driveway .. and just piled it up .... to make a mound ... sort of a small mountain ... that was the idea anyway ...

in other words.. i replicated a mini natural setting.. using a product similar to that found on the side of a mountain ... and did it entirely above ground ... thereby avoiding any native soil issues ....

ken

https://duckduckgo.com/?q=scree&t=ffcm&iax=images&ia=images

If you are raising the soil level, you should be thinking about the type of soil in the raised portion. Now that you have that all dug up, add some shredded leaves, straw or compost so it doesnt become compacted when you fill over it.

My soil is definitely 100% not clay. It's very loose when I dig into it and does it looks like clay soil in the picture? And Btw none of you can tell what kind of soil that is?

My question was is it really that crucial to amend the soil. Do I really need to take the time and money to amend(whether gravel or sand) if my soil is already well draining and if the bed is going to be slightly raised. 6 plants I'm going to use for the rock garden: achillea camtschatica, hylotelephium erythrostictum, sedum rupifragum, Dracocephalum argunense, chrysanthemum pacificum, and aquilegia flabellata. So If I don't amend it, all my plants will die of root rot? I just want to know how crucial it is to amend for these specific plants.

Btw my hylotelephium erythrostictum, and Dracocephalum was planted last year on a flat bed and they went through the very wet winter and survived. So doesnt that say anything about them being able to do fine even on non amended soil.

Cecily, I covered my chrysanthemum pacificum because it is Said that these Plants cannot tolerate wet winter soil according to the nursery I bought it from. Not because my soil is clay

Thank you Gardengal, no amending it is then. I know I always bring up root rot.. I'm absolutely terrified of those things. Once it happens then the fungus will spread in the soil of my whole garden and every plant will eventually contract the fungus. That's my main concern.

Also you bought this up at a good timing..starting from tomorrow all the way into a week and a half ahead Thursday is supposed to be all rain. I can't stop thinking if my plants will drown to death from a week and a half straight rain every single day in a row. I think I may have to buy more tarps.. Can you still say I am worrying too much about the upcoming rain even when it's rain for a week and a half straight? I don't even know anymore...this is stressing me out again

"Once it happens then the fungus will spread in the soil of my whole garden and every plant will eventually contract the fungus. That's my main concern."

Just not gonna happen!! Even in situations like Phytophthora ramorum (sudden oak death), which has a very wide range of host species - much more so than most other root rots - it will seldom wipe out an entire garden or nursery. Plant diseases - including root rots - tend to be very host specific.

And I don't know how to be any more clear than this: if your current soil drains reasonably well, then you do not have to worry about a week's worth of rain!! Period!!

Please, take it from someone living in a very winter wet and rainy climate and who has decades of experience with gardening........you do not need to be overly concerned about protecting plants from rain events nor that everything exposed to wet soil will develop root rots. It just doesn't work that way!

Ok you made me feel much better. Thanks :)

Do you know yet what plants will go into that bit? Some rock garden theme plants are not so fussy, the real alpine ones need soil amaneding in the senss that you want to ad gravel and sharp sand in order to ensure an excelent drainage.

I planted a kind of gravel bed with Thymus, Salvia etc., the original soil is loam, so too rich for this type of vegetation, the added pebbles and gravel helped a lot, and hardly ever any weeds, it was elevated about a foot or two.

Hey Gardengal.. So I found out just earlier one of my arisaema mayebarae has rotted. I just thought it went dormant super early but when I dug it up, it was just mushy and white and the whole bulb collapsed. It was super stinky and stink my whole glove real bad the odor even got to my hands. So of course I throw the bulb away in trash and take up some of the soil that was around it to get as much of the fungus out as possible.. I don't even know what I did wrong. I amended the soil with pine bark fines to ensure better drainage. I barely gave it supplemental water and just let the rain get it as the owner of the bulbs i bought it from kept warning me that this particular arisaema is very prone to rot. My 2 other same arisaema, at a different location than the one that rotted seems to be doing fine. Do you have any tips to prevent root rot in the future? Also one more important question. Since you said phytophthora is usually host specific, I can plant another plant at the same spot the arisaema rotted? I was originally going to put a saxifraga stolonifera there.

Linaria, I listed my plants in my previous comment. Are you familiar with any of them?

There are pathogenic root rots and then there are just root rots stemming from less than ideal drainage. The rot of the arisaema is likely due to the latter and not the former. Lots of bulbs and/or tuberous plants can suffer from rot if the drainage is not adequate. What caused the arisaema rot was NOT phytophthora!! You can plant anything you want there that will tolerate less than very fast drainage.

Well actually I think I will have to amend my soil with gravel. Apparently according to my arisaema my soil isn't well draining enough, even though it reasonably is enough for all my other plants. How do I properly amend my soil? I don't have the option to have somebody dump soil or scree delivered to my house nor will my dad allow me to do that. So I am going with the amending with gravel option but how can this be done? Do I really have to go back in my original plan to dig a 3 foot hole and amend all the loose soil with gravel and then pour it back in? How do you guys do it?

Can you use landscape timbers or bricks to create a raised bed?

I'd like to make my rock garden look as natural as possible so no bricks or any other material to make a border. I only do that for my herb garden. So in that case, would I still need to dig 3 feet below ground in a 14ftx7ft area? That sure will be a lot of labor especially since I'm the only one doing it so not sure if it is worth it or not. Unless it is critical for the plants and that they would inevitably die without a gravel amended soil 3 feet below

The vast majority of reading I have done recommends either a no-dig amendment method or tilling/digging and amending to about 10-12 inches. I looked through all my garden books and can't find anything recommending digging to three feet of depth! My soil has some clay content, so when I have built a new bed, I have generally chosen to hand dig and mix in my favorite bagged compost to improve the soil. The one time I rented a tiller, I found it didn't work as well as my trusty shovel and hand mixing. (In fact, the perennials in that particular bed have been the slowest growing!) However, I then tried layering with cardboard and mulch last fall for yet another bed, and frankly, that bed has been an absolute delight - hardly any effort and the soil is lovely, well draining, and easy to plant in. I will definitely use no-dig methods if I have time to wait patiently for my next new bed! For a rock garden, with plants that need even better drainage, I understand why you might add gravel, grit, or sand along with the compost, but regardless of what you amend the soil with, I can't fathom digging to three feet - I have planted trees without digging that deep. I think, maybe, the guys that installed my deck might have buried the concrete supports that deep, but other than that, I can't think of a reason to disturb the soil to that level.

Heruga, I really think you can get away with an easier method than the 'dig huge hole and mix with shedloads of gravel'. When you are planting, ensure there is a layer of gravel on the bottom of the hole - (dig wide rather than deep)- Pllace any plants a little higher than the soil level and mulch the whole planted area with fine pea shingle.gravel.clay pellets or whatever amendments. Use a finer grade (10mm) at the soil level as this will work its way deeper into the soil...and a larger grade (20mm) as the top layer.

Thanks Jenn and campanula. When I was researching the amendment issue for rock gardens some people say that amending just a foot or two with gravel, sand, compost etc is a waste of time because the perennial plant's roots will eventually extend below the amendment and now hit just the pure native soil. And if that is clay that is not good because you have amended soil on part of the plants rootball and the bottom part of the plants rootball is now touching the native clay soil. That is why I wondered if I really have to dig 3 feet but I guess plants rootballs only being partially exposed to the amendment is good enough I guess? Also campanula, is this a good product for gravel amendment? https://www.homedepot.com/p/Quikrete-50-lb-All-Purpose-Gravel-115150/100318444

Most of the world has only 18inches of topsoil before getting into subsoil, Heruga. Try not to fret. It is hard, as a newish gardener...but when you have killed millions, you get sort of hardened to murder (of plants).

Yep, the Quikcrete looks fine.

FWIW, more alpines tend to be alkaline lovers, often growing on high calcareous alpine meadows. The acidic ones tend to be more peat loving...such as haberlea, ramonda, cyclamen, some of the gentians. Have you looked at (or better yet, joined) NARGS - the North American Rock Gardening Soc. A trove of useful info...as is the Scottish rocks and alpine society (which has a very interesting geophyte section).

Most rock garden or alpine plants have very shallow root systems........that's why they are able to grow so successfully in very rocky/gravelly and lean soil. IMO (and that of Beth Chatto, who is probably best known for her rock or gravel gardens) amending other than to add rocks or gravel (if not of sufficient quantity in your situation) is counterproductive. I wouldn't bother digging any holes and adding amendments - certainly NO compost!! Rather, I'd just loosen/scrape the underlying clay the best I could so it wasn't a solid flat surface, then pile on a quantity of quite poor but well draining rocky, gravely or sandy soils so that you have a slightly sloped mound. Plant directly into that.

If you haven't already, I'd suggest acquiring a copy of Beth Chatto's Gravel Garden and read it thoroughly cover to cover!! That will tell you everything you need to know about designing, building and planting a rock garden.

Ok well taking some of your advices of not having to worry about amending it that deep, I did this. (first pic) I edged the bed out in a diameter shape(notice that my rock garden has to be in the middle of nowhere on a flat surface since there are no slopes in my yard and this area gets the most sun), tilled my whole bed with a tiller machine after applying 3 bags of sand I had left over, then I laid 10 bags of 60 lb gravel down and then raked it to make it even. Then I turned over the whole bed with a shovel(bed is 13ft wide and furthest point going vertical is 7. 5 ft). Then I tilled it again with the tiller machine. I still feel like the bed is too flat so I'm gonna dump 2 garbage can full of 2 inch rocks that I took from another area in my garden that I don't need there. And then I'll see if my bed is raised enough if not I guess I'll have to buy more gravel.

Also I put some small stones to border out the diameter bed(second pic, notice I'm only halfway there Cuz I gotta find more stones) does that look weird to you or is it ok? Does it also have any negative effects?

Also I tested my soil using the jar water method and turns out it is equal parts all sand, loam, and clay.

And yes.. I just looked at the North American rock garden society. Impressive list on the plants. I will browse through it and try to snatch some info but not sure if I want to pay to join.. I've already paid to join conifer society and I barely even use the site. I may buy Beth Chatto's book though since it is at an affordable price and may give me some direct lessons.