Powerful Penetrating Roots

What meadow plants will grow from seed and penetrate compacted soils? Burdock? Yes/no? What else? I ask because I may be rehabilitating a parking lot this year! I want plant pioneers to do the work of loosening things up.
Thanks!

Burdock would definitely work and grow in hard compacted area as well as dock. I have a hard time recommending burdock though as at my place it is super prolific and the seed pods are a huge negative of the plant.

Mullen is another good one. It seems to grow wherever the ground is hard.

Yarrow and plantain come to mind - maybe with a little clover mixed in for some nitrogen fixing. Lightly mulching the seed with grass clippings or even hay will retain moisture to help germination.

Julie Pastore wrote:What meadow plants will grow from seed and penetrate compacted soils? Burdock? Yes/no? What else? I ask because I may be rehabilitating a parking lot this year! I want plant pioneers to do the work of loosening things up.
Thanks!

Fortunately many meadow plants can penetrate compacted or heavy clay soils once they establish. The trick is to pick the right species that can do this and to create short-term conditions conducive to their establishing. The latter involves loosening the surface of any soil that's compacted so seeds that sprout have an easier time getting their roots started. Rototilling or harrowing is usually the best way to make that happen. A nurse crop also help with establishment. A nurse crop is basically a cover crop that will shelter the newly planted seeds without impairing their ability to grow by being too dense. I usually use an annual rye but there are many species that can fit this bill.

And as for matching plants with heavy clay soil, species that are native to most midwestern prairies are adept at handling those sort of conditions with relative ease. Part of the genius of meadow plants is that once they're established they can even thrive in difficult soils.  Echinacea purpurea, Heliopsis helianthoides, most Asclepias, Baptisia, Amsonia, Pycnanthemum, Silphium and Verbena, are some examples that pull this off with aplomb. Yarrow is definitely one such plant as well. I generally steer clear of burdock in meadows because of it's coarse appearance (I usually shoot for airier forms in meadow plants) and clingy burrs, but it is a very valuable plant – a delicious edible (gobo), a helpful medicinal, and birds love its seeds.  

Dandelions seem to be among the first plants I ever see growing in cracks of pavement, so I reckon that with their Taproot, they manage to drill through soil pretty well.

We bought the 3 abandoned lots behind us and garden them.  The center strip where they buried houses and covered in fill dirt are too hard to sink a shovel or pitchfork.  I smothered the grass and used a blend from prairie moon nurseries.  All of native meadow plants have deeper roots than grass.  Yellow dock, burdock, thistle and mugwort have also volunteered.  My happy finding though was that I could dig a hole for elderberry (with much difficulty) and they completely thrived.  They went from bare root to 15 foot monsters in a few short years!!!

I'd get forage radish growing wherever you have soil compaction problems.

It's an annual and has powerful and deep-seeking taproots that will remain in the soil and rot the next year, enhancing the soil biology and waterinfiltration.

The foliage is lush and very high protein. I planted thickly a patch of soil and feed  thinnings to my chickens, who love it.

Burdock and plantain both work where I live, as does red clover. I don't even try to dig burdock out from my garden beds any more -- just periodically chop and drop to add those deep soil minerals to my top soil.

Dandelions have one of the deepest taproots per plant height ratio of anything.  They also help correct nutrient imbalances.

Parsnips, which have a 2 foot fleshy root and which can be seeded by broadcasting, and oil seed radish are also good at breaking up hardpan.  Thistle grows prolifically in areas with lots of moisture, but it roots down to the hardpan and then horizontally for up to a couple feet -- which might require a century to correct the hardpan.