North America Non-native Plant

Potamogeton ×undulatus

Botanical name: Potamogeton ×undulatus

USDA symbol: POUN7

Native status: Not native but doesn't reproduce and persist in the wild

Potamogeton ×undulatus: The Mystery Hybrid Pondweed Meet Potamogeton ×undulatus, a plant that’s as mysterious as its scientific name suggests. The × in its name tells us this is a hybrid pondweed, and like many plant hybrids found in the wild, it keeps botanists on their toes and gardeners scratching their ...

Potamogeton ×undulatus: The Mystery Hybrid Pondweed

Meet Potamogeton ×undulatus, a plant that’s as mysterious as its scientific name suggests. The × in its name tells us this is a hybrid pondweed, and like many plant hybrids found in the wild, it keeps botanists on their toes and gardeners scratching their heads.

What Exactly Is This Plant?

Potamogeton ×undulatus belongs to the pondweed family, a group of aquatic plants that have mastered the art of living completely submerged in water. These aren’t your typical garden center finds – they’re specialized wetland dwellers that play crucial roles in aquatic ecosystems.

As a hybrid, this particular pondweed represents a natural cross between two parent Potamogeton species. Hybrids like this often occur where different pondweed species overlap in their natural habitats, creating offspring with characteristics from both parents.

Where Does It Call Home?

The geographical distribution of this specific hybrid remains somewhat of a botanical puzzle. However, we do know it has obligate wetland status in both the Midwest and Northcentral & Northeast regions of North America. This means you’ll almost always find it in wetland environments – it’s not just a water-lover, it’s a water-dependent plant that can’t survive without consistently wet conditions.

Should You Consider It for Your Garden?

Here’s where things get interesting (and a bit complicated). While pondweeds can be valuable additions to water gardens and natural ponds, Potamogeton ×undulatus presents some unique challenges:

  • Limited availability: Hybrid pondweeds are rarely commercially available
  • Identification difficulties: Even experts struggle to distinguish between closely related pondweed species and hybrids
  • Specialized requirements: Needs permanent, deep water conditions
  • Uncertain behavior: Hybrid plants can be unpredictable in garden settings

The Wetland Connection

Its obligate wetland status means this plant is a true aquatic specialist. In nature, these pondweeds serve important ecological functions:

  • Provide oxygen to water through photosynthesis
  • Offer shelter and breeding grounds for aquatic wildlife
  • Help stabilize sediments with their root systems
  • Filter water naturally

A Better Approach for Water Gardens

If you’re interested in adding aquatic plants to your water feature, consider these alternatives that are more readily available and better understood:

  • Native water lilies (Nymphaea species)
  • Wild celery (Vallisneria americana)
  • Eel grass (Zostera marina) for saltwater features
  • Other well-documented native pondweed species

The Bottom Line

Potamogeton ×undulatus represents the fascinating complexity of aquatic plant communities, but it’s not the most practical choice for home gardeners. Its hybrid nature, limited documentation, and specialized requirements make it better suited for scientific study than backyard water gardens.

If you’re passionate about supporting wetland ecosystems, focus on creating habitat with well-known native aquatic plants, or better yet, support local wetland conservation efforts. Sometimes the best way to appreciate a mysterious plant like this hybrid pondweed is to ensure its natural habitats remain protected for future generations to study and enjoy.

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

Midwest

OBL

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

Northcentral & Northeast

OBL

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

Potamogeton ×undulatus

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Alismatidae

Order

Najadales

Family

Potamogetonaceae Bercht. & J. Presl - Pondweed family

Genus

Potamogeton L. - pondweed

Species

Potamogeton ×undulatus Wolfgang ex Schult. & Schult. f. (pro sp.) [excluded] (pro sp.)

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