I just noticed the first flower and it looks like Prunella?

Could possibly be. Leaf shape , arrangement and veination fit, although the leaves seem a little thick and shiny. Can you show the flower?

Might possibly be Prunella grandiflora, due to the thick mat-like clumps, the thicker shinier leaves, and the fact they were planted by a gardener who was an avid seed collecter? Im really only familiar with P. lanceolata.

I'm only familiar with P. vulgaris.

It's finally blooming. Definitely Prunella. Any thoughts on species, and is Prunella sometimes included in flower-seed mixes?

There are 3 Prunella entities in North America. Prunella laciniata has cream colored flowers and serrated leaves. The other 2 are Prunella vulgaris subsp. vulgaris, which is a non native introduction, and Prunella vulgaris subsp. lanceolata which is native to North America. Subspecies vulgaris has broadly rounded leaf bases, while subspecies lanceolata has wedge shaped,(cuneate) leaf bases. The leaf bases on your plants look cuneate to me. I like the native Prunella but it spreads prolifically from seeds, and it can also spread by rhizome. Im using Prunella to smother Creeping Charlie. P. lanceolata doesnt play well with short growing plants. It invaded my Antennaria and it would have smothered it if I hadnt removed it. Bees love it and you can dry and use the leaves for tea. There's no difference between a subspecies and a variety. They are synonyms. and interchangable.

Thanks Jay. After enjoying the flowers for a few days, I will be removing all of it.

I forgot about the earlier comments and was approaching it as something that showed up in your property, but because the previous owner grew unusual plants it's possible these plants are Prunella grandiflora. They don't look like my P. lanceolata, but you're digging them out anyway. Prunella grandiflora isnt documented being in North America so please destroy them to prevent them from getting loose into the environmrnt. It has a huge potential to wreak havoc in natural ecosystems.