North America Native Plant

Stiff Buttonweed

Botanical name: Diodia apiculata

USDA symbol: DIAP

Life cycle: perennial

Habit: subshrub

Native status: Native to Puerto Rico âš˜ Native to the U.S. Virgin Islands  

Synonyms: Diodella rigida (Willd. ex Roem. & Schult.) Small (DIRI3)  âš˜  Diodia rigida (Willd. ex Roem. & Schult.) Cham. & Schltdl. (DIRI4)   

Stiff Buttonweed: A Lesser-Known Native Gem for Caribbean Gardens If you’re gardening in Puerto Rico or the U.S. Virgin Islands and looking to embrace truly local flora, you might want to get acquainted with stiff buttonweed (Diodia apiculata). This perennial native might not be the flashiest plant in your garden ...

Stiff Buttonweed: A Lesser-Known Native Gem for Caribbean Gardens

If you’re gardening in Puerto Rico or the U.S. Virgin Islands and looking to embrace truly local flora, you might want to get acquainted with stiff buttonweed (Diodia apiculata). This perennial native might not be the flashiest plant in your garden center, but it represents an authentic piece of Caribbean botanical heritage that’s worth considering for the right garden setting.

What Exactly Is Stiff Buttonweed?

Stiff buttonweed belongs to the coffee family (Rubiaceae) and lives up to its name with a sturdy, herbaceous growth habit. As a perennial forb, it’s a non-woody plant that comes back year after year, though it never develops the thick, woody stems you’d see on shrubs or trees. You might also encounter this plant listed under its scientific synonyms Diodella rigida or Diodia rigida in older botanical references.

Where Does It Call Home?

This plant is a true Caribbean native, naturally occurring in Puerto Rico and the U.S. Virgin Islands. If you’re gardening in these tropical territories, you’re working with a plant that has been thriving in your local ecosystem long before any of us arrived on the scene.

Should You Grow Stiff Buttonweed?

Here’s where things get a bit tricky – stiff buttonweed falls into that category of native plants that haven’t made it into mainstream horticulture. While this means it’s an authentic choice for native plant enthusiasts, it also means there’s limited information about its garden performance and care requirements.

The Case for Growing It

  • True native status: Supporting local ecosystems by choosing indigenous plants
  • Perennial nature: Once established, it should return year after year
  • Low maintenance potential: Native plants typically require less intervention than non-natives
  • Unique garden choice: You won’t see this in every neighborhood garden

The Challenges

  • Limited availability: You probably won’t find this at your local garden center
  • Unknown ornamental value: We don’t have clear information about its flowers, foliage appeal, or size
  • Care requirements unclear: Specific growing needs aren’t well-documented

Growing Stiff Buttonweed: Working with the Unknowns

Since detailed cultivation information for Diodia apiculata is scarce, your best bet is to mimic its natural habitat conditions. As a Caribbean native, it likely appreciates:

  • Warm, tropical conditions year-round
  • Well-draining soil (most tropical natives don’t like waterlogged conditions)
  • Partial to full sun exposure
  • Natural rainfall patterns supplemented with irrigation during dry spells

Where to Find It

Your best sources for stiff buttonweed will likely be:

  • Native plant societies in Puerto Rico or the Virgin Islands
  • Botanical gardens with native plant programs
  • Specialized native plant nurseries
  • Plant swaps with other native plant enthusiasts

The Bottom Line

Stiff buttonweed represents an interesting choice for the adventurous native plant gardener. While we can’t promise it’ll be the star of your landscape design, it offers the satisfaction of growing something truly local to your region. If you’re passionate about supporting indigenous flora and don’t mind a bit of gardening mystery, this could be a worthwhile addition to your plant collection.

Just remember – when dealing with lesser-known natives, patience and observation are your best tools. Keep notes on how it performs in your garden, and consider sharing your experiences with local native plant groups to help build the knowledge base for future growers.

Stiff Buttonweed

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

Diodia L. - buttonweed

Species

Diodia apiculata (Willd. ex Roem. & Schult.) K. Schum. - stiff buttonweed

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