North America Non-native Plant

Oldenlandia Corymbosa Var. Corymbosa

Botanical name: Oldenlandia corymbosa var. corymbosa

USDA symbol: OLCOC

Life cycle: annual

Habit: forb

Native status: Non-native, reproduces and persists in the wild in Pacific Basin excluding Hawaii  

Oldenlandia corymbosa var. corymbosa: A Lesser-Known Pacific Basin Forb If you’ve stumbled across the name Oldenlandia corymbosa var. corymbosa in your botanical wanderings, you’re looking at one of those plants that keeps a pretty low profile. This annual forb might not be the showstopper of the plant world, but it ...

Oldenlandia corymbosa var. corymbosa: A Lesser-Known Pacific Basin Forb

If you’ve stumbled across the name Oldenlandia corymbosa var. corymbosa in your botanical wanderings, you’re looking at one of those plants that keeps a pretty low profile. This annual forb might not be the showstopper of the plant world, but it has carved out its own niche in the Pacific Basin region.

What Is Oldenlandia corymbosa var. corymbosa?

This plant belongs to the forb family – think of forbs as the herbaceous plants that aren’t grasses but also don’t have woody stems. They’re the soft-stemmed plants that complete their entire life cycle in one growing season, then call it quits. Oldenlandia corymbosa var. corymbosa fits this description perfectly, living fast and focusing all its energy into one productive year.

As a non-woody plant, it keeps things simple structurally. No thick bark or permanent branches here – just soft, green stems that do their job and then gracefully bow out when the season ends.

Where Does It Call Home?

This particular variety has made itself comfortable in Guam and Palau, where it grows as an introduced species. While it’s not native to these Pacific islands, it has established itself and reproduces on its own without needing human help to keep going.

The Garden Reality Check

Here’s the thing about Oldenlandia corymbosa var. corymbosa – it’s not exactly what you’d call a garden center darling. Information about its cultivation, appearance, and growing requirements is surprisingly scarce, which tells us this isn’t a plant that’s made its way into mainstream gardening.

Since it’s an annual forb, you can expect it to:

  • Complete its full life cycle in one year
  • Have soft, non-woody stems
  • Focus its energy on flowering and seed production
  • Require replanting or self-seeding each year

Should You Grow It?

The honest answer? There’s not enough readily available information about this specific variety to make strong recommendations about growing it. Its low profile in horticultural circles suggests it’s not particularly ornamental or useful in typical garden settings.

If you’re gardening in Guam or Palau and are curious about this plant, you might encounter it growing wild. However, since it’s a non-native species, consider focusing your gardening energy on native plants that support local ecosystems and wildlife.

Better Alternatives

Instead of trying to cultivate this relatively unknown variety, consider exploring native forbs and annual plants from your region. Native species offer several advantages:

  • Better adapted to local growing conditions
  • Support native wildlife and pollinators
  • Require less maintenance once established
  • Help preserve local biodiversity

The Bottom Line

Oldenlandia corymbosa var. corymbosa represents one of those plants that exists quietly in the botanical world without making much of a splash in gardens. While there’s nothing inherently wrong with this annual forb, its limited availability of cultivation information and non-native status suggest your gardening efforts might be better invested in native alternatives that offer more reliable growing guidance and ecological benefits.

Sometimes the most interesting plants are the ones we observe in the wild rather than try to tame in our gardens. If you encounter this variety in its naturalized habitat, take a moment to appreciate it as part of the diverse tapestry of plant life, but consider native options when planning your own landscape.

Oldenlandia Corymbosa Var. Corymbosa

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Rubiales

Family

Rubiaceae Juss. - Madder family

Genus

Oldenlandia L. - oldenlandia

Species

Oldenlandia corymbosa L. - flat-top mille graines

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA