North America Native Plant

Flat-top Four O’clock

Botanical name: Mirabilis glabrifolia

USDA symbol: MIGL4

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Allionia corymbosa (Cav.) Kuntze (ALCO8)  âš˜  Mirabilis corymbosa Cav. (MICO13)  âš˜  Oxybaphus corymbosus (Cav.) Standl. (OXCO7)   

Flat-Top Four O’Clock: A Hidden Gem for Texas Native Gardens Meet the flat-top four o’clock (Mirabilis glabrifolia), a charming native Texas perennial that’s practically built for our challenging climate. This delightful forb might not be the showiest plant in the garden center, but it’s exactly the kind of reliable, low-maintenance ...

Flat-Top Four O’Clock: A Hidden Gem for Texas Native Gardens

Meet the flat-top four o’clock (Mirabilis glabrifolia), a charming native Texas perennial that’s practically built for our challenging climate. This delightful forb might not be the showiest plant in the garden center, but it’s exactly the kind of reliable, low-maintenance native that seasoned gardeners treasure.

What Makes Flat-Top Four O’Clock Special

This herbaceous perennial belongs to the four o’clock family, and true to its name, it puts on its best show in the late afternoon and evening hours. The small, tubular flowers typically bloom in shades of pink to purple, creating a subtle but lovely display that’s perfectly timed for evening garden strolls.

You might also see this plant listed under its botanical synonyms: Allionia corymbosa, Mirabilis corymbosa, or Oxybaphus corymbosus. Don’t let the scientific names intimidate you – this is simply a testament to how botanists have refined their understanding of this species over time.

Where Does It Come From?

Flat-top four o’clock is a true Texas native, found naturally in central and south Texas. As a plant that evolved in our region, it’s perfectly adapted to handle our hot summers, occasional droughts, and variable weather patterns. This native status makes it an excellent choice for gardeners looking to support local ecosystems while creating beautiful, sustainable landscapes.

Why Grow Flat-Top Four O’Clock?

Here’s where this unassuming plant really shines:

  • Drought tolerance: Once established, it requires minimal supplemental watering
  • Low maintenance: This isn’t a plant that demands constant attention
  • Evening interest: Adds life to your garden during those pleasant evening hours
  • Pollinator support: Attracts moths and other nocturnal pollinators
  • Native ecology: Supports local wildlife and fits naturally into Texas landscapes

Perfect Garden Settings

Flat-top four o’clock works beautifully in several garden styles:

  • Rock gardens: Its low-growing habit and drought tolerance make it ideal for rocky, well-draining areas
  • Xeriscape landscapes: Perfect for water-wise gardening approaches
  • Native plant gardens: An authentic addition to Texas native plantings
  • Naturalistic designs: Blends seamlessly into more informal, prairie-style landscapes

Growing Conditions and Care

The beauty of native plants like flat-top four o’clock lies in their simplicity. Here’s what this plant prefers:

  • Sunlight: Full sun to partial shade
  • Soil: Well-draining soil is essential – this plant doesn’t tolerate soggy conditions
  • Water: Drought tolerant once established, but benefits from occasional deep watering during extreme dry spells
  • Hardiness: Suitable for USDA zones 8-10, making it perfect for most of Texas

Planting and Care Tips

Getting started with flat-top four o’clock is refreshingly straightforward:

  • Plant in spring after the last frost when soil temperatures are warming
  • Ensure excellent drainage – amend heavy clay soils with compost or sand if needed
  • Water regularly the first season to help establish roots, then reduce watering frequency
  • Don’t panic if the plant goes dormant during extreme summer heat – this is normal
  • Minimal fertilization needed; too much can actually reduce flowering

The Evening Garden Experience

One of the most delightful aspects of growing flat-top four o’clock is discovering how it transforms your evening garden experience. As the day cools and you step outside to enjoy the pleasant evening air, this plant comes alive with fresh blooms and subtle fragrance that attracts fascinating nocturnal pollinators.

Is This Plant Right for Your Garden?

Flat-top four o’clock is an excellent choice if you’re looking to create a low-maintenance, water-wise garden that celebrates Texas native plants. It’s particularly well-suited for gardeners who appreciate subtle beauty over flashy displays and want to support local ecosystems. However, if you’re seeking bold, all-day color or plants for heavy shade, you might want to consider other options alongside this native gem.

For Texas gardeners committed to sustainable, regionally appropriate landscaping, flat-top four o’clock represents exactly the kind of plant that makes native gardening both beautiful and rewarding. It’s proof that sometimes the most valuable plants are the ones that quietly do their job while asking for very little in return.

Flat-top 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

Mirabilis L. - four o'clock

Species

Mirabilis glabrifolia (Ortega) I.M. Johnst. - flat-top 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