North America Native Plant

Burrowing Four O’clock

Botanical name: Okenia hypogaea

USDA symbol: OKHY

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Burrowing Four O’Clock: Florida’s Underground Mystery Plant Meet one of Florida’s most enigmatic native plants: the burrowing four o’clock (Okenia hypogaea). This little-known annual is as mysterious as its name suggests, spending much of its life literally underground. If you’re a native plant enthusiast looking for something truly unique, this ...

Rare plant alert!

Region: Conservation status by state

Status: S3?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Burrowing Four O’Clock: Florida’s Underground Mystery Plant

Meet one of Florida’s most enigmatic native plants: the burrowing four o’clock (Okenia hypogaea). This little-known annual is as mysterious as its name suggests, spending much of its life literally underground. If you’re a native plant enthusiast looking for something truly unique, this rare Florida endemic might just capture your imagination—though growing it comes with some important considerations.

What Makes This Plant So Special?

The burrowing four o’clock belongs to the Four O’Clock family (Nyctaginaceae), the same group that includes the colorful mirabilis flowers many gardeners know and love. But unlike its showy cousins, Okenia hypogaea has evolved a fascinating underground lifestyle that makes it one of Florida’s most unusual native plants.

As an annual forb, this plant completes its entire life cycle in just one growing season. It’s a non-woody plant that produces new growth from buds located at or below ground level—a perfect adaptation for its burrowing nature.

Where Does It Call Home?

This Florida endemic is found exclusively in the Sunshine State, making it a true local treasure. Its extremely limited range adds to both its mystique and its conservation importance.

A Word of Caution: Rarity Matters

Before you start planning where to plant burrowing four o’clock in your garden, there’s something crucial you need to know. This species has a Global Conservation Status of S3?, which indicates there’s significant uncertainty about its population status. This rarity designation means we need to be especially thoughtful about how we interact with this plant.

If you’re interested in growing Okenia hypogaea, here are the responsible approaches:

  • Only obtain plants or seeds from reputable native plant nurseries that ethically propagate their stock
  • Never collect from wild populations
  • Consider supporting conservation efforts for this species instead of growing it
  • Focus on other native Four O’Clock family members that are more readily available

What We Know About Growing Conditions

Due to its rarity and underground nature, detailed growing information for burrowing four o’clock is limited. However, based on its family characteristics and Florida native status, we can make some educated guesses about its preferences:

  • Likely thrives in Florida’s warm, subtropical climate
  • As an underground specialist, probably prefers well-draining sandy soils
  • Being native to Florida, it’s adapted to the state’s seasonal rainfall patterns
  • May require specific soil conditions or microclimates that aren’t well understood

Garden Role and Design Potential

Given its underground growth habit and rarity, burrowing four o’clock isn’t your typical landscape plant. If you were fortunate enough to grow it responsibly, it would serve more as a conservation piece and conversation starter than a traditional ornamental. Its unique growth pattern makes it better suited for specialized native plant collections or botanical gardens rather than typical residential landscapes.

Supporting Florida’s Native Plant Heritage

While growing burrowing four o’clock might not be practical for most gardeners, you can still support Florida’s incredible native plant diversity by choosing other native Four O’Clock family members or Florida endemics that are more readily available. Consider these alternatives:

  • Other native Nyctaginaceae species that are less rare
  • Common Florida native wildflowers that support local ecosystems
  • Native plants that provide similar ecological functions

The Bigger Picture

Okenia hypogaea represents something precious: Florida’s unique evolutionary heritage. Every rare endemic species like this one tells a story of adaptation, survival, and the incredible diversity that makes Florida’s ecosystems so special. While we may not all be able to grow this mysterious underground dweller, we can appreciate its role in the complex web of native Florida flora.

By choosing native plants for our gardens—even the more common ones—we’re supporting the same ecosystems that shelter rare treasures like the burrowing four o’clock. Sometimes the best way to honor a rare plant is to create habitat for the entire community of species it depends on.

Burrowing Four O’clock

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Caryophyllidae

Order

Caryophyllales

Family

Nyctaginaceae Juss. - Four o'clock family

Genus

Okenia Schltdl. & Cham. - okenia

Species

Okenia hypogaea Schltdl. & Cham. - burrowing four o'clock

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