Looking for the right low ground cover for an awkward/specific spot

I'm looking for a pretty, very low ground cover to plant in a zone 7-8 climate. It needs to be ok with clay, it would be under the canopy of an oak tree, and would likely get mowed indiscriminately from time to time. It needs to naturalize and not need caring for. I'm especially interested if this plant can also be attractive and possibly have some purple, either foliage or flowers at some time. Edited to add that this would be a non-sanctioned planting in a casually maintained (by others) semi-public space.

Violets?

Yarrow (red flowered variety)

Phil Stevens wrote:Violets?

Violets were my first thought as well. I wasn't sure if I had seen them under oaks but if I can find some seeds to get in there. I thought Johnny Jump Ups too but think of them in more full sun settings. They are pretty tenacious though - I see them growing through cracks in concrete with no care.

Veronica (speedwell) is another possibility. More on the blue end of things rather than purple but will spread and self-seed as eagerly as violets. It would die back and pretty much disappear over winter, though.

Phil Stevens wrote:Veronica (speedwell) is another possibility. More on the blue end of things rather than purple but will spread and self-seed as eagerly as violets. It would die back and pretty much disappear over winter, though.

That is a great idea! Good height, hardiness. Lovely color too. It would be nice to possibly find several types that would creep across the area under the radar until established and provide color and coverage at different times of year.

A few more to throw in the mix: lobelia, and purple flowered bulbs like bluebells and grape hyacinths.

Mercy Pergande wrote:I'm looking for a pretty, very low ground cover to plant in a zone 7-8 climate. It needs to be ok with clay, it would be under the canopy of an oak tree, and would likely get mowed indiscriminately from time to time. It needs to naturalize and not need caring for. I'm especially interested if this plant can also be attractive and possibly have some purple, either foliage or flowers at some time. Edited to add that this would be a non-sanctioned planting in a casually maintained (by others) semi-public space.

I have a plant that makes a great ground cover. It is a Blue Pimpernel, Anagallis Monellii





Most people are familiar with the Scarlet Pimpernel, Anagallis arvensis:





https://permies.com/t/157111/Living-Mulch-Mediterranean-Food-Forest#1231678

Wow that color is gorgeous! I will see if I can find some of those seeds too!

How dry / wet is the soil? I assume with clay the soil can be water-logged, but I don't know how much rain you get. What weeds grow there currently? That might be a good indicator of what will thrive there (some weeds do better with really moist conditions, other in really dry conditions).

How shaded is it under the oak tree? Is it like a single tree in a field (relatively high light), or heavily shaded with trees all around?

I could imagine dutch white clover forming a low and low-maintenance ground cover, but I think it might want enough light.

Violets are a great suggestion, I find them in my wet clay soils in shade (I'm in east TN in the Great Appalachian Valley, technically a rain forest). Violet seeds are not viable for long, but they grow commonly as a weed so I would just look to dig up violets from somewhere else and transplant them under the oak to get them started.

Comfrey isn't low-growing but will grow back readily from being mowed and will shade out other weeds and will provide lots of nutritious mulch when mowed (assuming you are mowing and that's why you want low-growing?), it's a common permaculture trick to put comfrey under the canopy of trees and to treat them as a chop and drop nutrient pump.

In addition to all of your wonderful suggestions, I am contemplating some kind of forget-me-not; I think it's a little on the tall side but could maybe do well on the edges of the area which are less tended.

The area is on a slope so while it is a heavy clay soil, it won't really get too boggy.

If anyone has thoughts on this type of flower, I am all ears. I think with a mix of several of the previously mentioned plants, it could make for a lovely succession of blooms.