North America Native Plant

Roundleaf Lobelia

Botanical name: Lobelia rotundifolia

USDA symbol: LORO3

Life cycle: perennial

Habit: subshrub

Native status: Native to Puerto Rico  

Roundleaf Lobelia: A Hidden Gem for Wetland Gardens If you’re looking to add some native Caribbean flair to your wetland garden, let me introduce you to a lesser-known treasure: roundleaf lobelia (Lobelia rotundifolia). This charming perennial might not be the showiest plant in your garden, but it’s got some serious ...

Roundleaf Lobelia: A Hidden Gem for Wetland Gardens

If you’re looking to add some native Caribbean flair to your wetland garden, let me introduce you to a lesser-known treasure: roundleaf lobelia (Lobelia rotundifolia). This charming perennial might not be the showiest plant in your garden, but it’s got some serious wetland credentials that make it worth considering for the right spot.

What Exactly Is Roundleaf Lobelia?

Roundleaf lobelia is a perennial herb that belongs to the bellflower family. Don’t expect towering heights or woody stems here – this little guy is what botanists call a forb, which is just a fancy way of saying it’s a soft-stemmed plant that dies back to the ground each year and regrows from its roots. Think of it as the herbaceous cousin of those flashy cardinal flowers you might know.

Where Does It Call Home?

This native beauty is exclusive to Puerto Rico, making it a true Caribbean endemic. If you’re gardening in Puerto Rico or trying to create an authentic tropical wetland garden, this plant offers genuine local character that you won’t find anywhere else in the world.

The Wetland Specialist

Here’s where roundleaf lobelia gets really interesting – it’s what we call an obligate wetland plant. That means it almost always lives in wetlands and really, really likes its feet wet. We’re talking consistently moist to saturated soils, not just the occasional watering.

Should You Plant Roundleaf Lobelia?

The honest answer? It depends on your garden situation. Here’s the breakdown:

You’ll Love It If:

  • You have a bog garden, rain garden, or consistently wet area
  • You’re creating a native Puerto Rican landscape
  • You enjoy growing unique, specialized plants
  • You want to support local ecosystems with authentic native species

Skip It If:

  • Your soil drains well or tends to dry out
  • You’re looking for a low-maintenance, drought-tolerant plant
  • You want something with showy flowers or dramatic foliage
  • You don’t live in a tropical or subtropical climate

Growing Roundleaf Lobelia Successfully

Climate Requirements

This tropical native thrives in USDA hardiness zones 10-11, where temperatures stay warm year-round. If you’re gardening outside of Puerto Rico or similar Caribbean climates, you might need to treat it as a specialty greenhouse plant.

Soil and Water Needs

The key to success with roundleaf lobelia is understanding its wetland nature:

  • Plant in consistently moist to wet soil
  • Ensure good organic content in the soil
  • Avoid letting the soil dry out completely
  • Consider planting near water features or in rain gardens

Planting Tips

Since this is a specialized native plant, sourcing can be challenging. If you do find roundleaf lobelia:

  • Plant during the wet season for best establishment
  • Choose the wettest spot in your garden
  • Mulch around plants to help retain moisture
  • Be patient – specialized plants often take time to establish

The Bottom Line

Roundleaf lobelia isn’t going to be the star of most gardens, but for the right gardener in the right location, it’s a fascinating piece of Puerto Rico’s natural heritage. If you have the perfect wetland spot and a love for native plants, this little perennial could be exactly what you’re looking for. Just remember – it’s all about location, location, location, and in this case, that location better be wet!

For most gardeners outside of specialized wetland situations, you might want to consider other lobelia species or native wetland plants that are better suited to your local conditions. But if you’re up for the challenge and have the right environment, roundleaf lobelia offers a unique opportunity to grow something truly special.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Caribbean

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Roundleaf Lobelia

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

Campanulales

Family

Campanulaceae Juss. - Bellflower family

Genus

Lobelia L. - lobelia

Species

Lobelia rotundifolia Juss. ex A. DC. - roundleaf lobelia

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