Teucrium canadense is native throughout the United States and (as the species name suggests) Canada too. One of the quickest ways to check whether a species is native is to use the USDA Plants Database, see link at bottom. Just type in the scientific name in the right-hand box (near top of page), and make sure the words "Scientific Name" appear in the left-hand box.

Here is a link that might be useful: Welcome to the PLANTS National Database

It's listed as invasive in a couple of states. Where I live in southcentral Texas, it doesn't seem to be, at least in the wild. I guess it's sort of a wetlands plant, and we don't have too many wetland areas around here.

Actually, I read somewhere else that Teucrium canadense is considered "aggressive / rhizomatous", which means that it is likely to spread a lot. (A plant can be both native to your region and "locally invasive" in your garden.)

The wetland status in most of the eastern and central US (including Missouri) is "FACW-". This is a technical term meaning that more than 2/3 of the native population is found in wetlands, but only slightly more than 2/3, so it is not unusual to find the plant in non-wetland locations.

Here is a better link to the USDA page for this plant:

Here is a link that might be useful: Teucrium canadense

Just found this post again. I guess I didn't realize a native plant could be invasive. Mine does seem to have spread quite a bit but it's the only place on my property that I've seen it. It came up on the east side of my house where a gutter drains. I assume if it were horribly invasive, it would be more common. Maybe it's too dry in the rest of the yard.

Christie from Missouri: Consider the eastern red cedar Juniperus virginiana, a native which is invasive throughout our state and has swallowed up thousands of acres of glades and rocky prairies in the wake of reduced fire frequency. Plants that were non-invasive under the ecological conditions under which they evolved can become invasive when their environment changes.

Germander is rather aggressive in moister parts of prairie plantings, but in my experience, it does subside after several years as various tall grasses, sedges and taller forbs become established. Since cattle don't like it, I could see how the USDA might characterize it as invasive in pasture situations, where it may well be even more persistant than in a prairie planting.

its not invasive if its in its natural home, in a mature wetlands.

it might be invasive in ur garden. it might be invasive in a cow pasture. it might even be invasive in another part of the world. but if placed within a natural wetland community, its just another part of the community.

fyi, ive never found this spp to be a problem and its kinda cute.

froggy