Living in the same area for many years means that I see some of the same plants over and over. It’s kind of nice, like seeing old friends. Sometimes, plants that you’ve still seen many times still have the power to impress you more than usual. Bluets (Houstonia spp.) have been that way for me lately.
Of the 8 species of Houstonia found in Georgia, there are spring-blooming ones and summer-blooming ones. Right now, the spring ones are winking up at us from very low on the ground. You probably won’t be surprised to know that these small plants in the madder family (Rubiaceae) have some small native relatives like buttonweed (Diodia), bedstraw (Galium) and partridgeberry (Mitchella). You’d be more surprised to know that buttonbush (Cephalanthus) and Pinckneya are also in that family!
The second species is a perennial one: Houstonia caerulea also has a small rosette of tiny leaves. It usually grows a bit taller than the annual species but still not more than 6 inches. Common names include azure bluet and Quaker Ladies. I usually find this one in moist, mossy areas such as a damp ravine. I’m still trying to get this one going in my yard as well. I think it was eaten last year by a more aggressive neighbor. Notice that this species has a yellow center; it shares this characteristic with thymeleaf bluet, Houstonia serpyllifolia, which grows in the mountains, as well as with the Southern annual bluet, Houstonia micrantha.
A uniquely Coastal Plain species is the round-leaved bluet, Houstonia procumbens. Tiny flowers sprout from creeping foliage in the spring, and the bright whiteness of the flowers evokes another one of its common names: innocence. I saw it on the side of a road in the Okefenokee Swamp during a trip with the Georgia Botanical Society.
The remaining 3 species are summer bloomers. Houstonia canadensis is found in North Georgia and recognized by the presence of basal leaves at flowering time compared to the others in summer. Houstonia longifolia and Houstonia purpurea are similar and more widespread, except for the shape of the leaves. I believe what I found once (and I’m not even sure where) is the long-leaved bluet.
Now that you know these little guys, keep an eye out for them. They are sweet little members of our native plant communities.