North America Native Plant

Rough Strongbark

Botanical name: Bourreria radula

USDA symbol: BORA2

Life cycle: perennial

Habit: shrub

Native status: Native to the lower 48 states âš˜ Native to Puerto Rico  

Synonyms: Bourreria revoluta Kunth (BORE5)  âš˜  Bourreria succulenta Jacq. var. revoluta (Kunth) O.E. Schulz (BOSUR)   

Rough Strongbark: A Resilient Native Shrub for Coastal Gardens If you’re gardening in South Florida and looking for a tough, low-maintenance native shrub that can handle whatever Mother Nature throws at it, let me introduce you to rough strongbark (Bourreria radula). This unassuming but resilient plant might just be the ...

Rare plant alert!

Region: Conservation status by state

Status: S2?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Rough Strongbark: A Resilient Native Shrub for Coastal Gardens

If you’re gardening in South Florida and looking for a tough, low-maintenance native shrub that can handle whatever Mother Nature throws at it, let me introduce you to rough strongbark (Bourreria radula). This unassuming but resilient plant might just be the perfect addition to your coastal landscape – though it’s definitely not for everyone!

What is Rough Strongbark?

Rough strongbark is a perennial shrub that typically grows 4-5 meters (13-16 feet) tall, though it can sometimes reach greater heights depending on growing conditions. True to its name, this plant has distinctively rough, leathery leaves that feel almost sandpapery to the touch. Don’t let the rough exterior fool you though – this shrub produces clusters of small, fragrant white flowers that are absolutely delightful.

You might also encounter this plant listed under its botanical synonyms Bourreria revoluta or Bourreria succulenta var. revoluta in older gardening references.

Where Does Rough Strongbark Grow Naturally?

This native beauty calls Florida and Puerto Rico home, with most populations found in the Florida Keys and coastal areas. It’s perfectly adapted to life by the sea, having evolved to handle salt spray, sandy soils, and the occasional hurricane.

Why Consider Planting Rough Strongbark?

Here’s where rough strongbark really shines:

  • Coastal champion: This shrub laughs in the face of salt spray and sandy soils that would make other plants wilt
  • Drought warrior: Once established, it needs very little supplemental watering
  • Wildlife magnet: Those fragrant white flowers attract butterflies and native bees
  • Low maintenance: Perfect for gardeners who want beauty without the fuss
  • Native credentials: Supporting local ecosystems never goes out of style

The Reality Check: Is This Plant Right for You?

Before you get too excited, let’s talk limitations. Rough strongbark is really only suitable for USDA hardiness zones 10b-11, which means unless you’re in South Florida or similar tropical/subtropical climates, this isn’t going to work in your garden. It also has a Global Conservation Status of S2?, which suggests it may have some rarity concerns – so if you do decide to plant it, make sure you’re sourcing from reputable native plant nurseries that propagate responsibly.

Growing Rough Strongbark Successfully

The good news? If you’re in the right climate zone, this plant is refreshingly easy to grow:

  • Soil: Sandy, well-draining soil is ideal – think beachside conditions
  • Sun: Full sun to partial shade
  • Water: Drought tolerant once established, but appreciates occasional deep watering during dry spells
  • Salt tolerance: Excellent – perfect for coastal properties

Planting and Care Tips

Plant rough strongbark in spring after any threat of cold weather has passed. While it can handle brief temperature dips, hard freezes will damage or kill the plant. Choose a spot with good drainage – soggy feet are about the only thing that will make this tough customer unhappy.

Pruning is minimal – just remove any dead or damaged branches and shape lightly after flowering if desired. The plant’s natural form is quite attractive, so don’t feel compelled to over-manage it.

Perfect Garden Companions

Rough strongbark fits beautifully into coastal gardens, xeriscape designs, and native plant collections. Consider pairing it with other salt-tolerant natives like coontie, firebush, or sea grape for a truly authentic South Florida landscape.

The Bottom Line

Rough strongbark is a fantastic choice for gardeners in its native range who want a low-maintenance, wildlife-friendly shrub that can handle coastal conditions with aplomb. Just remember to source plants responsibly and be realistic about whether your climate can support this tropical beauty. If you’re outside zones 10b-11, consider exploring native alternatives better suited to your region – every area has its own wonderful native shrubs waiting to be discovered!

Rough Strongbark

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

Lamiales

Family

Boraginaceae Juss. - Borage family

Genus

Bourreria P. Br. - strongbark

Species

Bourreria radula (Poir.) G. Don - rough strongbark

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