Most gardeners plant to attract pollinators. I found one that was already doing the attracting — before I even knew what it was.
In 2024, as I began forming a new pollinator habitat, small seedlings started coming up on their own. When they bloomed, I posted them to iNaturalist and got my answer: painted spurge, Euphorbia heterophylla, a native plant I’d never seen or even heard of before. It’s easy to overlook, and easy to confuse with its showier lookalike, paintedleaf (Euphorbia cyathophora), which carries the bright red-and-green bracts most people picture when they hear “painted.” Painted spurge has none of that. Its flowers are pale green, sometimes with a faint pink blush, with no showy petals at all — plain enough that you could stand right next to a blooming plant and not realize you were looking at a flower.
It’s also an annual, living fast and relying entirely on reseeding to return each year. Its life cycle can run as short as six to eight weeks from germination to seed, letting it push through several generations in a single season. When the seed capsules ripen, they don’t rely on wind or hitchhiking burrs — they split open explosively, flinging seeds a short distance from the parent plant. Between the speed and the volume — a single plant can produce thousands of seeds — it’s an aggressive reseeder. But in my own experience, that doesn’t translate into an aggressive plant. In three years of looking, I’ve only found it growing wild in two or three places, and the one sizable patch I found was in a regularly mowed field — exactly the kind of open, low-competition ground it seems to need. Give it other plants to compete with and it struggles. It’s also shallow-rooted and comes up with the lightest tug, so if it ever shows up somewhere you don’t want it, removing it takes seconds. It’s a plant that reseeds readily but doesn’t take over — it just fills empty ground while it’s empty.
Painted spurge growing among lantana and Spanish needle along a fence line — its upright stems and flat-topped flower clusters stand out above the surrounding growth.
The full plant habit — multiple upright stems topped with inconspicuous flower clusters, easy to walk right past.
That plainness is exactly what makes what happens next so surprising.
Every Euphorbia flower is built around a small cup-shaped structure called a cyathium — a feature unique to this genus and its close relatives. Sitting right beside the female flower part, each cyathium carries a nectar gland: a tiny “vase” of nectar, easy to miss unless you’re looking closely. It isn’t unique to painted spurge — the structure shows up across the Euphorbia genus — but on a plant this unassuming, finding it feels like uncovering a hidden feature nobody mentioned.
And insects have found it in numbers I didn’t expect. Using iNaturalist’s “visited flower of” observation field — a place where users can record exactly which insect was seen on exactly which plant — I’ve logged 98 observations covering over 60 different species on this one plant, not just a lot of visits from a handful of regulars. Wasps make up the largest share by far: digger wasps, mason wasps, scoliid wasps, thread-waisted wasps, one after another. Bees show up too, from the Western Honey Bee and American Bumble Bee down to several sweat bee species. Flies, ants, a couple of beetles, even a stink bug round out the list. Butterflies, interestingly, barely show up at all — just three species in the entire dataset. Painted spurge, it turns out, isn’t a butterfly plant. It’s everything else’s plant.
Gold-marked Thread-waisted Wasp (Eremnophila aureonotata) feeding at a painted spurge cyathium.
Swift Feather-legged Fly (Trichopoda pennipes), a tachinid fly, nectaring at the gland.
A Cassius Blue (Leptotes cassius) — one of only three butterfly species I’ve recorded on painted spurge — with proboscis down in the gland.
Including, on occasion, a mosquito.
I’ve watched — and photographed — a mosquito working its proboscis down into one of those tiny nectar vases, feeding exactly like the wasps and bees around it. It’s worth pausing on, because it runs against nearly everyone’s assumption about what mosquitoes do. In truth, nectar is the primary food source for mosquitoes of both sexes; only females, after mating, need a blood meal to develop eggs. A mosquito visiting a flower isn’t an exception to normal mosquito behavior — it’s the behavior, just not the part anyone usually sees. And no, growing this plant doesn’t mean inviting mosquitoes into your yard any more than growing it invites wasps or bees from somewhere else — it simply means giving something that’s already out there one more place to feed.
A mosquito feeding at a painted spurge cyathium — proof that even mosquitoes rely on nectar.
Painted spurge will probably never be a plant people seek out. It has no bracts to admire, no fragrance to notice, nothing that would earn it a spot on a garden center shelf. But for a plant with almost nothing to look at, it’s doing an outsized amount of quiet work — one inconspicuous little vase at a time.
iNaturalist is a free website (and companion app) where anyone can photograph and record wildlife sightings, which are then identified by the community and added to a public, searchable database.
If you’d never heard of Painted Spurge before today, and found some value in learning about it, that’s exactly the kind of thing this site is for. If you’d like to show your appreciation, you can buy me a coffee at buymeacoffee.com/kcthetc1 — it goes straight toward keeping articles like this one coming.
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