Native Plants

Clammy Clover

Trifolium obtusiflorum

USDA symbol: TROB2

annual forb

Lower 48 states: native

Looking for a native ground cover that’s both practical and beneficial to local wildlife? Meet clammy clover (Trifolium obtusiflorum), a charming little annual that deserves more attention in native plant gardens across the West Coast. Clammy clover is a native annual forb—basically a soft-stemmed plant without woody growth—that belongs to ...

Clammy Clover: A Native Ground Cover Worth Getting to Know

Looking for a native ground cover that’s both practical and beneficial to local wildlife? Meet clammy clover (Trifolium obtusiflorum), a charming little annual that deserves more attention in native plant gardens across the West Coast.

What Is Clammy Clover?

Clammy clover is a native annual forb—basically a soft-stemmed plant without woody growth—that belongs to the legume family. Don’t let the clammy name put you off; this refers to the slightly sticky texture of its leaves and stems, not any unpleasant qualities! Like other clovers, it features the classic three-leaflet design and produces small, delicate flower clusters.

This native beauty is sometimes known by its botanical synonym Trifolium tridentatum var. obtusiflorum, but whatever you call it, it’s a genuine West Coast native with plenty to offer your garden.

Where Does Clammy Clover Call Home?

Clammy clover is native to California and Oregon, making it a perfect choice for gardeners in these states who want to support local ecosystems. It’s naturally adapted to the varied climates and conditions found throughout these regions, from coastal areas to inland valleys.

  • Species observed
  • No observations

Why Grow Clammy Clover?

There are several compelling reasons to consider adding this native clover to your landscape:

  • Native pollinator magnet: The small flowers attract native bees, butterflies, and other beneficial insects
  • Soil improvement: As a legume, it fixes nitrogen in the soil, naturally fertilizing surrounding plants
  • Low maintenance: Once established, it requires minimal care and watering
  • Wildlife habitat: Provides food and shelter for small wildlife and beneficial insects
  • Erosion control: Its spreading growth habit helps stabilize soil

Garden Design and Landscape Uses

Clammy clover works beautifully in several garden settings:

  • Native plant gardens: Perfect for authentic regional landscapes
  • Wildflower meadows: Adds texture and nitrogen-fixing benefits
  • Naturalized areas: Great for low-maintenance, eco-friendly spaces
  • Ground cover: Fills in bare spots with native beauty

Growing Conditions and Care

One of clammy clover’s best features is its adaptability. Here’s what this flexible native prefers:

  • Sunlight: Full sun to partial shade
  • Soil: Well-draining soils; tolerates various soil types
  • Water: Moderate water needs; drought-tolerant once established
  • Hardiness zones: USDA zones 8-10
  • Wetland tolerance: Facultative—can handle both wet and dry conditions

Planting and Care Tips

Growing clammy clover is refreshingly straightforward:

  • Timing: Direct seed in fall or early spring for best results
  • Seeding: Scatter seeds over prepared soil and lightly rake in
  • Watering: Keep soil moist until germination, then reduce watering
  • Maintenance: Minimal care needed—this native knows how to take care of itself!
  • Annual lifecycle: Will self-seed in favorable conditions

The Bottom Line

Clammy clover might not be the showiest plant in your garden, but it’s exactly the kind of hardworking native that makes ecosystems thrive. If you’re gardening in California or Oregon and want to support local wildlife while enjoying a low-maintenance ground cover, this modest little clover could be just what you’re looking for. Sometimes the most valuable garden plants are the ones that quietly do their job while supporting the bigger picture of regional biodiversity.

Trifolium obtusiflorum is also known as...

Often we refer to plants by their common names. When shopping for plants the scientific name is the best way to positively identify the plant species you desire. But some plants have more than one name! While it doesn't happen often, nurseries might display one name while you're searching for another. Trifolium obtusiflorum is also known as:

Trifolium tridentatum var. obtusiflorum | USDA symbol: TRTRO

Why do some plants have more than one name? Over time plant species may be renamed for a few reasons:

  1. Botanists in different regions named the same plant without knowing it had already been classified.
  2. A species was reclassified after scientific advances in, for example, DNA analysis.
  3. Slight variations within a species are sometimes mistakenly identified as entirely new species.

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 care and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection can be if you don't have the right information. While tags on nursery plants 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. You might be surprised to learn that popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. The table below gives insight into the preferred growing conditions of this plant throughout its geographical distribution.

Region
Preferred Habitat

Arid West (AZ, CA, CO, ID, MT, NV, NM, OR, TX, UT, WA, WY)

Facultative

Western Mountains, Valleys, and Coast (AZ, CA, CO, ID, MT, NV, NM, OR, SD, UT, WA, WY)

Facultative
Wetland Glossary
Obligate Wetland
Facultative Wetland
Facultative
Facultative Upland
Obligate Upland
Almost always occurs in wetlands
Usually occurs in wetlands but may occur in non-wetlands
Can occur in wetlands and non-wetlands
Usually occurs in non-wetlands but may occur in wetlands
Almost never occurs in wetlands

Classification

Group: Dicot
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Rosidae
Order: Fabales
Family: Fabaceae Lindl. - Pea family
Genus: Trifolium L. - clover

Species: Trifolium obtusiflorum Hook. f. - clammy clover

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