North America Non-native Plant

Trifolium Squarrosum

Botanical name: Trifolium squarrosum

USDA symbol: TRSQ2

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

Sea Clover: A Mediterranean Ground Cover for Coastal Gardens If you’ve ever wandered through Mediterranean coastal landscapes and noticed small, unassuming clover-like plants carpeting the ground near the shore, you might have encountered Trifolium squarrosum, commonly known as sea clover or rough clover. This charming little annual brings a touch ...

Sea Clover: A Mediterranean Ground Cover for Coastal Gardens

If you’ve ever wandered through Mediterranean coastal landscapes and noticed small, unassuming clover-like plants carpeting the ground near the shore, you might have encountered Trifolium squarrosum, commonly known as sea clover or rough clover. This charming little annual brings a touch of Mediterranean magic to gardens, though it’s definitely not your typical backyard plant.

What Makes Sea Clover Special?

Sea clover is a member of the legume family, sporting the classic three-leaflet leaves that make clovers instantly recognizable. What sets this species apart is its preference for coastal conditions and its delicate white to pale pink flower heads that appear in small, rounded clusters. The plant gets its rough common name from the somewhat coarse texture of its foliage compared to other clovers.

This Mediterranean native originally calls the coastal regions of Europe and North Africa home, where it thrives in sandy soils and salt-laden air. It’s perfectly adapted to the boom-and-bust cycle of Mediterranean climates, growing rapidly during cool, wet winters and completing its life cycle before the harsh summer heat arrives.

Should You Grow Sea Clover?

Here’s where things get interesting. Sea clover isn’t native to North America, so before you fall head-over-heels for this Mediterranean charmer, consider a few factors:

  • Climate compatibility: This plant thrives in USDA zones 8-10, particularly in areas with Mediterranean-like climates
  • Garden style: It’s perfect for naturalized areas, coastal gardens, or Mediterranean-themed landscapes
  • Maintenance level: Once established, it’s remarkably low-maintenance and drought-tolerant
  • Ecological impact: As a non-native, it won’t provide the same benefits to local wildlife as indigenous plants

If you’re passionate about supporting native ecosystems, consider exploring native clovers and legumes in your region instead. Many areas have beautiful indigenous clovers that provide superior habitat and food sources for local pollinators and wildlife.

Growing Sea Clover Successfully

If you decide sea clover fits your garden vision, here’s how to help it thrive:

Ideal Growing Conditions

  • Sunlight: Full sun is essential for healthy growth
  • Soil: Well-draining sandy or loamy soil; avoid heavy, water-logged conditions
  • Water: Drought-tolerant once established, but appreciates regular water during germination
  • Salt tolerance: Handles coastal conditions and salt spray remarkably well

Planting and Care Tips

Sea clover is refreshingly easy to grow if you can provide the right conditions:

  • Timing: Direct seed in fall or early spring when temperatures are cool
  • Spacing: Scatter seeds broadly for naturalized areas, or space plants 6-8 inches apart
  • Germination: Keep soil consistently moist until seedlings establish
  • Maintenance: Minimal care required; allow plants to self-seed for naturalized colonies

What to Expect

Sea clover typically grows 6-12 inches tall with a spreading, somewhat prostrate habit. As an annual, individual plants complete their entire life cycle in one growing season, but they often self-seed readily in suitable conditions. The small flowers appear in spring and early summer, attracting bees and other small pollinators.

The plant’s low, spreading growth makes it excellent ground cover for areas where you want something more interesting than grass but don’t need anything too formal or structured.

The Bottom Line

Sea clover can be a delightful addition to the right garden setting, particularly if you’re creating a Mediterranean-inspired landscape or working with coastal conditions. However, if your goal is to support local ecosystems and native wildlife, you’ll likely find better options among your region’s indigenous plant communities.

Whatever you choose, the most important thing is selecting plants that thrive in your specific conditions while aligning with your gardening goals and environmental values. Happy gardening!

Trifolium Squarrosum

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Trifolium L. - clover

Species

Trifolium squarrosum L.

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