My rock hard & sticky clay has lots of curly dock (low calcium and extremely high magnesium, phosphorus and potassium). True, my soil was tested exceedingly high in magnesium and soil test recommended gypsum for my soil pH of 7.7 (that was brand new soil when the house was first built) .. now it's still dense clay but more acidic due to our high rain in recent years. Below is a pic. of curly dock, note the pea-gravel mixed in. Below soil helps roses to bloom more with high magnesium & phosphorus & potassium:

The place where my black gumbo-clay is more fluffy with less magnesium, below pic. of Wild buckwheat signifies low phosphorus and an excess of potassium. This is where I scoop up soil to top blackspot-prone roses:

The weeds that I have the most in my black clay is Lambsquarters grows in low phosphorus, high potassium soils. Neighbors bought bagged garden soil to grow their roses, and lambsquarters became invasive, their roses are always healthy with zero blackspots due to high potassium. Below is lambsquarter weed:

Below excerpt from the old farmer's almanac link weeds to the types of soil ... useful link has pics. associated with each weed.

https://www.almanac.com/weeds-indicator-plants

• Bindweed grows in crusty or compacted soil.
• Chickweed and chicory like rich soil—high in nitrogen—and will grow well in alkaline, compacted soil.
• Common groundsel is an indicator of rich soil. Remember: “If you have groundsel, you have good soil!”
• Crabgrass grows where the soil has been depleted of nutrients and is low in calcium.
• Dandelions generally indicate soil that is low in calcium, as well as compacted.
• Dock and goldenrod grow in wet, poorly drained soil.
• Fragile fern grows in near-neutral, dry conditions.
• Henbit indicates high nitrogen.
• Knapweed indicates rich soil, high in potassium.
• Knotweed grows where the ground is compacted.
• Lambsquarters indicates rich soil, high in nitrogen.
• Moss of most kinds indicate soggy, acidic soil that is low in nutrients.
• Mullein grows in acidic soil with low fertility.
• Mustard grows in dry, sandy soil, high in phosphorus.
• Ostrich fern indicates an exceptionally fertile location.
• Oxalis, or wood sorrel, indicates low calcium and high magnesium.
• Ox-eye daisies grow in acidic, often soggy soil with poor fertility.
• Plantain grows in compacted, sour soil with low fertility and often indicates heavy clay.
• Peppergrass indicates sweet soil.
• Pigweed grows in rich soil with high levels of readily available nitrogen.
• Purslane prefers rich soil and is an indicator of high phosphorus.
• Quackgrass will grow in heavy clay or compacted soil.
• Queen Anne’s lace grows where the soil is poor, but on the sweet side.
• Ragweed indicates low fertility.
• Stinging nettle grows in rich, acidic soil.
• Sheep sorrel indicates dry, sandy, acidic soil depleted of nutrients and low in calcium.
• Yarrow grows where potassium and fertility are low and the soil is sandy and dry.
• https://www.almanac.com/weeds-indicator-plants

From Straw: If I ever move to a new garden, the weeds I want which indicate good soils are Common Groundsel with yellow flowers, I saw such weeds in rich bagged top soil:

Below Henbit (purple flowers) that grow in spring indicates high nitrogen. Bunnies like to eat Henbit in my garden, now I realize that's good soil high in nitrogen:

Below Chickweed grows in rich soil high in nitrogen, esp. in alkaline & compacted clay. Chickweed is edible and bunnies love them:

Below pigweed grew berserk in the MG-bagged garden soil that my neighbor used in her new garden. Pigweed grows in rich soil with high levels of readily available nitrogen.

Below is young pigweed plant:

I never like the look of knap weed (pic. below) and always pull them up before they give purple flowers. Below Knapweed indicates rich soil, high in potassium.

Below pic. Bindweed grows in crusty or compacted soil. Stringy & climbing Bindweed with white flowers (like morning-glory) is a BIG PROBLEM in my compacted alkaline clay. The neighbor treated bindweed by chopping it at root level, then doused it with Lawn high nitrogen fertilizer. High nitrogen fertilizer is acidic and burns the root.

"Bindweed has a deep and extensive root system which stores nutrients for regrowth. Although it can grow in a range of conditions, bindweed prefers heavy clay soil."

Previous years I dug up dandelions until my hand bled, this year I spread pelletized lime, with a drastic decline in dandelions (dandelions thrive in low-calcium soil). Below link has slide-show pics. of weeds: https://bcfarmsandfood.com/weeds-that-indicate-soil-conditions/

I pH tested the compact area of my clay, and it's still alkaline (blue in red cabbage juice), I never see buttercup weed in my garden. Buttercup (yellow flower) indicates acidic, poorly-drained soil. Growing up in Michigan I saw lots of horsetail in a swamp. Horsetail indicates light, sandy, slightly acidic soil.

In contrast, chickweed indicates good & moist soil. "Chickweed grows in neutral, moist, sometimes heavy soils. Healthy chickweed indicates fertile soil." Have plenty of chickweed sprouting from bagged soil (black peat clay here).

Purple Deadnettle, a member of the mint family, often indicates neutral, nutrient-rich soil. Below Purple Deadnettel is VERY INVASIVE in my clay. Spent lots of time pulling them up in spring time.

Around roses I have lots of sweet clover (yellow flowers) which is indicative of pH 6 to 7, plus high potassium and low nitrogen.

https://bcfarmsandfood.com/weeds-that-indicate-soil-conditions/

From below link: Gardening Know How: Common Garden Weeds: Identifying Weeds By Soil Type https://www.gardeningknowhow.com/lawn-care/lgen/what-the-weeds-in-your-lawn-are-telling-you.htm

Acidic soil – Acidic soils are usually a result of insufficient oxygen with weeds like: Hawkweed (yellow tiny daisy), Sorrel (skinny thin leaves), Moss, Plantain (broad leaves).

Alkaline soil – Chicory, Queen Anne’s lace, Spotted spurge, Chickweed.

When my house was built back in 2001, there were lots of Queen Anne's Lace in the icky sub-soil. Then the builder topped with new soil. I still have lots of spotted spurge in areas of compacted clay that bunnies like to eat, see below spotted spurge.

Below weeds indicate poor and low fertility soil, except for clover (fixes nitrogen plus high in potassium): Yarrow, Ragweed, Dandelion (low calcium soil), Thistle, Crabgrass, Plantain, Clover, Mullein, Sorrel, Wild carrot or Queen Anne’s lace.
https://www.gardeningknowhow.com/lawn-care/lgen/what-the-weeds-in-your-lawn-are-telling-you.htm

My life was a slave to weeds prior to garden lime. I spent 2 hrs. per week during spring to dig up hundreds of dandelions until my palm bled. I pulled up weeds along the driveway until I developed an allergic reaction, and scratched my fingers until they were bloody. Sprinkling garden lime over weeds solved that problem.

Learned that trick from my neighbor: she put bagged Menards topped soil on her lawn, and it sprouted 5 different types of weeds, she told me that her lawn company will spread lime to kill the weeds. They did and weeds gone.

When I topped my rose garden with horse manure (stable here used oyster shell lime to deodorize) .. I HAD ZERO WEEDS in my rose beds. Garden lime is cheap at $5 per 50 lb., plus it has magnesium to "glue" up soil for moisture retention, calcium is to UP the pH to kill weeds.

Cluster-root weeds don't like high pH, and dandelions thrive where soil is low in calcium. Below is a section of my garden in late fall: the place near trees' roots are depleted of calcium & nitrogen (trees steal lots of calcium & nitrogen from soil). Such place grew icky mushrooms with tons of rain in late fall, so I spread garden lime, and NO MORE MUSHROOMS on lawn. No dandelions either.

My main weeds in the HT rose bed are oxalis and some kind of weed that is a vine with a blue flower.... not sure what it is (not morning glory- I am in zone 10 Florida. I will try and get a picture of it. Maybe someone can identify it,)

In my old roses garden the main weed is some kind of grass. Not sure what it is either. Grass B Gone does not touch it. It is a grass and not sedge. I think it is torpedo grass.

My rose shrub (was mostly DA until my flood) had mostly dollar weed and the same torpedo (I think grass).

Sharon: I have a few siblings in Fort Meyers and Port Charlotte, FL. Is your soil wet and sandy? Dollar weed likes wet areas according to U. of Florida.

I don't have Oxalis (yellow flowers), but I have bind weed with vine similar to morning glory with small white flowers. Bind weed also comes with blue flower, see below link:

https://www.gardenia.net/plant/convolvulus-sabatius-bindweed

I don't have torpedo grass but I have quackgrass (grows in compacted clay). My clay is dense & heavy. The top black clay can get acidic with tons of rain, but the bottom yellow clay is alkaline with dolomitic rocks.

Strawchicago, I followed the link. My blue flower weed is not bind weed. I am not sure what it is but will take a picture next time it blooms... and it will because I can not pull it out fast enough.

My oxalis are pink. They are quite pretty for a weed.... but they just take over. Here is a link of what mine look like https://pixels.com/featured/pink-sorrel-oxalis-articulata-in-flower-bob-gibbonsscience-photo-library.html

My dollar weed area is a more moist area, but it definitely is not sandy. It is probably the best dirt I have actually seen in all of South Florida.... nice dark rich.... it even has earthworms which my other two rose beds do not have. I think the reason that it is so rich is that I put in lots of horse manure, and shredded banyan leaves. I do that to the other beds, but I think since they are dryer it just crumbles into smaller and smaller particles, it doesn't seem to actually break down into dirt..... In fact the other two beds seem to sometimes repel water because the broken down leaf litter doesn't absorb anything, whereas this DA bed is a sponge....

Agree that horse manure is very rich & dark humus. It's dense & fertile. I no longer get horse manure since my clay is already black & dense humus, so I bought coarse sand & gypsum to make my alkaline clay fluffier. My black gumbo clay was tested very high in organic matter.

Below link classified weeds according to low-fertiliy & dry, or high-fertility, or acidic clay, or alkaline clay:

https://www.sierra-worm-compost.com/soil-fertility.html

"Chronic dry soil - mullein, prickly thistle, Queen Ann's lace.

Low fertility/compacted soil - crab grass, shepherd's purse, queen Ann's lace, black medic (clover).

Acidic Clay Soil - areas that receive high rainfall (Eastern U.S. and Pacific Northwest) tend to have slightly to moderately acid soil ... wherever you find pine and oak trees, you will usually have acidic soil. Weeds: sorrel (yellow flower wood sorrel that looks like clover), annual bluegrass, dandelion, plantain or buckhorn (loves moist & fertile).

Acidic & fertile soil - dandelions grow in areas of low-calcium, stinging nettle, red or white clover, lambsquarter or pigweed, purslane. Highly acidic soil should have between 7-9 lbs of calcitic lime/100 sq. ft applied in the fall. Mildly acidic soil requires about 5 lbs/100 sq. ft. Wood ash is a fast-acting alkalizer. It is generally recommended that no more than 25 lbs of ash/1000 sq. feet

Alkaline soil - wild carrot (Queen Ann's lace), chick weed, spotted plurge. Adding gypsum, calcium sulphate or powdered elemental sulphur will also help lower pH."

https://www.sierra-worm-compost.com/soil-fertility.html

Since I have bad ragweed allergy, below is common ragweed:

Below is giant ragweed:

For weeds in my state of IL, I found the below link with pictures:

http://weeds.cropsci.illinois.edu/weedid.htm

Oxalis, or wood sorrel, indicates low calcium and high magnesium. This weed is most invasive in my high magnesium clay. Yellow wood oxalis is often mistaken for yellow clover, but Oxalis has green kidney-seed-pods that explodes when touched. From scott's lawn care website: "Oxalis, also known as wood sorrel, is a perennial weed that is often mistaken for clover. The leaves of wood sorrel fold down at night and open during the day to harvest sunlight. They produce seed capsules that explode when touched, spreading seed in every direction."

Ok.... my blue weed has a couple of blooms.... hopefully someone can identify it and then tell me how to eradicate it. It is one nasty weed. It spreads underground and if you try to pull it out and it breaks off it will sprout new runners. If you do pull it out and drop a piece on the ground it will grow roots and start to spread. Plus while it is growing it vines across the top of the soil where it also puts down new roots and sends out runners...... I hate this weed.

It can get very bushy and up to 2 feet high and keeps spreading

The leaves look similar to blue passion flower weed:

https://www.weedbusters.org.nz/what-are-weeds/weed-list/blue-passion-flower/

Thanks straw for trying to identify it. I do have passion vine for my butterflies. This weed is not that. Too bad because the caterpillars would keep it under control. I guess my pictures are not too good. This flower is about 1/8 to 1/4 inch.

It might be blue potterweed in florida, see below link:

https://www.south-florida-plant-guide.com/porterweed.html

I have one weed in my garden that I can't identify, even after looking up weeds in IL, will post pic. later.

Sharon, it looks like a vinca relative. But I don't remember it from MS.

We have lots of Cat's paw in our lawn (flower looks like dandelion). I am constantly dealing with quack grass/crab grass.

Wood sorrel gets into my rose pots, and I think does a bit of changing the soil, because those pots don't respond to fertilizing the same, but I could be wrong.

Amaranth did not grow in my garden this year, nor it's relative pigweed, because we forgot to top-dress with compost....won't do that again!

I checked Wood Sorrel (Shamrock) and it doesn't fix nitrogen like clover (a legume). Wood Sorrel steals nutrients from soil so I always pull it out.

From below link: "Is wood sorrel nitrogen fixing?

All legumes have nitrogen fixing nodules on their roots. The plants take nitrogen from the atmosphere and store it up. The plant that's called Shamrock is actually Oxalis, commonly called Wood Sorrel. These plants have clover-like leaves but they grow from bulbs or rhizomes (thickened roots)".

https://treehozz.com/what-is-the-difference-between-clover-and-wood-sorrel

I have been able to identify my blue weed. It is Commelina.... Asiatic dayflower.

Supposedly one can eat it..... not going to.....

It is considered an invasive weed.... and I can see why because every time you pull it up it gets worse.

I am trying to figure out by googling why soil it likes so I can do the opposite to get rid of it..... maybe I can ask the neighbors if they are hungry and they can come and harvest it.... LOL

I have lemon balm and a few sites state that lemon balm tea works better than any sleeping pill. I agree, Lemon Balm tea is very delicious (10 times better than mint tea) and it calms and wipes away any worries plus makes me fall asleep immediately. However it gets invasive now since we have tons of rain this year. The plus is the roots are shallow, I can kill a big clump of Lemon Balm in less than 10 min.

The hardest weed to kill is Canadian thistle, the roots are very deep, reaching down to sub-clay layer. Here's a excerpt from below link: "Weeds tells a story. Cockle Burr grows in the deficiency of the availability of the mineral silver. Bull Thistle grows in the deficiency of available zinc. Musk or Canada Thistles grow in the deficiency of available phosphorus, and Leafy Spurge grows in the deficiency of the available nickel. Every mineral has a job.

Without the proper level of available Calcium, these other trace minerals will not be available to the plant. It is easy to react to symptoms (like weeds) instead of dealing with the problems causing the symptoms."

https://www.ag-usa.net/Calcium%20-%20%20Is%20your%20soil%20trying%20to%20tell%20you%20something.htm

From Straw: Shamrock (yellow Wood Sorrel) gets very invasive after 2 decades of high-rain. When I first moved here in 2001, the new topsoil was very alkaline at pH 8 and there's no shamrock. But as we get lots of rain, the top soil becomes more acidic and there's an explosion of Shamrock. As I dig holes for roses, I take the bottom soil (very alkaline at below 2 feet) and throw on top where I want to suppress the weeds. Yellow Wood Sorrel is indicative of high magnesium and low calcium, which corresponds to my soil test.

An excerpt from below link on weeds to tell salt content of soil:

"As the salt in your soil builds, your soil is telling you exactly what’s going on. For example, when dandelions grow, salt is starting to cause a problem. Next, if you notice along with dandelions, kochia is starting to grow, the salt content is steadily increasing. The next salt loving plant to move in will be foxtail.

When the PH of soil is too high or too low, there is a deficiency of available calcium."

https://www.ag-usa.net/Calcium%20-%20%20Is%20your%20soil%20trying%20to%20tell%20you%20something.htm

Dandelions grow well in the front (by the mailbox) where I scooped up heavily-salted snow from the road and dumped it by the mailbox's curb. So I dug out the dandelions, and filled the holes with VERY ALKALINE top soil (pH near 8) and no more dandelions. Dandelions thrive in clay low in calcium and high in magnesium, and even worse when the pH drops with acidic rain.

bump this up.