I have a number of “ornamental oreganos” in my garden and was trying to sort them out, when I noticed one with white flowers I couldn’t imagine purchasing. I was reading some are both ornamental and tasty
I was working on a “green seasoning” recipe that called for oregano, so I started tasting! 
They are all aromatic, but this white one has pretty spicy leaves!
Does anyone know what it might be?
Could it be a Mexican oregano? I have one that looks lie that, it gets about 4’ tall, dies back in winter, and comes back in spring after heavy pruning. It has white flowers, not sure if they look exactly like yours, but close. And the flavor is quite spicy. I prefer it to others that I’ve had.
That’s an interesting idea! I have dried Mexican Oregano because a taco recipe I make a lot calls for it, but I don’t know if I can tell what it tastes like.
Looking it up!
This one has been flowering
and I am starting to suspect something is spreading from seed, and maybe reverting back to a less attractive variety than I remember buying.
This is the white one, now replanted in a container.
Mine don’t look like that, I guess it['s still a mystery. I’ll take some photos tomorrow
I can’t really say it looks like that, but I am reminded I have two plant ID apps!, one of which is plantnet!
ETA They don’t all look exactly alike, but I guess that’s allowed.
And
The one you have with larger purple flowers looks like nepitella to me - mine is flowering at the moment too.
My Greek and Italian oreganos are also flowering but the flowers are white and much smaller than the nepitella. Here’s a shot of the Italian next to the nepitella:
Thank you! Looked it up and see it is also called calamint and I remember planting calamint!
So the one to the left of the one with the purple flowers is the Greek oregano? That looks exactly like my white one! I don’t remember planting edible oregano outside of a container. It’s Greek to me! 
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Thank you too @ChristinaM !
No, the one in the second pic to the left of the nepitella is my Italian oregano. Its flowers are arranged in heavy little clusters that sort of look like miniature hops. Here’s the Greek:
The flowers on the Greek are more separate and wispy than the Italian.
Anyway, if you planted calamint (nepitella) at some point, I’m sure that’s what your purple flowered plant is. It is a very vigorous reseeder in my garden - volunteers everywhere. You’re probably enjoying the same phenomenon!
