Tall Cottongrass: A Striking Native Sedge for Wet Gardens
If you’re looking to add some serious wow factor to your wetland garden or rain garden, let me introduce you to one of nature’s most delightful surprises: tall cottongrass (Eriophorum angustifolium). This perennial sedge might not win any beauty contests during most of the growing season, but come summer, it transforms into something absolutely magical that’ll have your neighbors doing double-takes.
What Makes Tall Cottongrass Special
Don’t let the name fool you – this isn’t actually a grass at all! Tall cottongrass is a sedge, part of the Cyperaceae family, and it’s got a personality all its own. During most of the year, it looks like a fairly ordinary grass-like plant with green foliage and a moderate texture. But here’s where it gets exciting: in summer, this unassuming plant produces the most incredible cotton-white, fluffy seed heads that dance in the breeze like tiny pom-poms.
Growing up to 2 feet tall with an erect, bunch-forming growth habit, tall cottongrass has a moderate growth rate and a long lifespan, making it a reliable performer in the right conditions.
Native Status and Where It Grows
Here’s something to get excited about – tall cottongrass is impressively native! This hardy sedge calls home to Alaska, Canada, Greenland, most of the lower 48 states, and even St. Pierre and Miquelon. You’ll find it naturally growing across an enormous range, from Alberta and British Columbia all the way to Maine and New Mexico, and everywhere in between including Colorado, Michigan, Minnesota, Montana, and many other states.
The Ultimate Wetland Plant
If there’s one thing tall cottongrass is absolutely committed to, it’s wet feet. This plant has Obligate Wetland status across every region where it grows, which means it almost always occurs in wetlands. Think of it as nature’s way of saying I live in the swamp, and I love it!
This makes tall cottongrass perfect for:
- Rain gardens and bioswales
- Bog gardens
- Pond margins and water garden edges
- Naturalized wetland areas
- Native plant gardens with consistent moisture
Growing Conditions That Make It Happy
Tall cottongrass is surprisingly adaptable when it comes to soil texture – it’ll grow in coarse, medium, or fine-textured soils. However, it’s quite particular about a few things:
Moisture: This plant has high moisture requirements and zero drought tolerance. If you can’t keep it consistently wet, this isn’t the plant for you.
pH: It prefers acidic conditions, thriving in soils with pH between 4.0 and 6.5.
Sun: Despite being shade intolerant, it needs full sun to perform its best.
Climate: Hardy in USDA zones 2-7, this tough cookie can handle temperatures as low as -43°F and needs at least 100 frost-free days.
Soil fertility: Medium fertility requirements – not too rich, not too poor.
Planting and Care Tips
Getting tall cottongrass established is relatively straightforward if you can meet its moisture needs:
Propagation: You can grow it from seed (there are about 160,000 seeds per pound!), bare root plants, or sprigs. Seeds are routinely commercially available.
Planting density: Plan for 4,800 to 11,000 plants per acre, depending on your desired coverage.
Timing: Plant in late spring when the soil is workable but still consistently moist.
Maintenance: Once established, this is a low-maintenance plant. It doesn’t require fertilization, has no known toxicity issues, and won’t become aggressive in your garden.
Wildlife and Ecological Benefits
While tall cottongrass is wind-pollinated (so it won’t attract bees and butterflies), those fluffy seed heads aren’t just for show – they provide excellent nesting material for birds. The plant also helps with erosion control in wet areas and contributes to the overall ecosystem health of wetland environments.
Why You Should (Or Shouldn’t) Plant It
Plant it if: You have a consistently wet area that needs something special, you’re creating a native wetland garden, or you want a conversation starter that’s both beautiful and ecologically valuable.
Skip it if: Your garden conditions are anything less than consistently moist, you need something that tolerates drought, or you’re looking for a pollinator magnet.
Tall cottongrass might seem like a niche plant, but for the right garden and the right gardener, it’s an absolute treasure. Those summer seed heads alone are worth the effort – imagine a whole patch of them swaying in the breeze like nature’s own cotton candy factory!
