North America Native Plant

Sedge

Botanical name: Carex ×olneyi

USDA symbol: CAOL4

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Carex ×olneyi: A Rare Native Sedge for Water Gardens If you’re looking to add authentic New England character to your water garden or wetland restoration project, Carex ×olneyi might just be the hidden gem you’ve been searching for. This native sedge brings a touch of wild beauty to soggy spots ...

Carex ×olneyi: A Rare Native Sedge for Water Gardens

If you’re looking to add authentic New England character to your water garden or wetland restoration project, Carex ×olneyi might just be the hidden gem you’ve been searching for. This native sedge brings a touch of wild beauty to soggy spots where other plants fear to tread.

What Makes This Sedge Special?

Carex ×olneyi, commonly known simply as sedge, is a perennial grass-like plant that’s as native as they come to the northeastern United States. This isn’t your typical lawn grass – it’s part of the sedge family (Cyperaceae), which means it’s perfectly adapted to life in wet, marshy conditions where regular grasses would throw in the towel.

What makes this particular sedge interesting is that it’s actually a natural hybrid, which partly explains why you won’t find it everywhere. It’s like nature’s own custom blend, created where two parent sedge species meet and mingle.

Where You’ll Find It Growing Wild

This sedge keeps a pretty exclusive address list. In the wild, you’ll only find Carex ×olneyi in three New England states: Connecticut, Massachusetts, and Rhode Island. It’s definitely more of a regional specialist than a widespread wanderer.

Why Consider Growing This Sedge?

Here’s where this sedge really shines in the garden:

  • Perfect for problem spots: Got a soggy area where nothing else will grow? This sedge thrives in consistently wet conditions
  • Low maintenance: Once established, it pretty much takes care of itself
  • Native wildlife support: Provides nesting material and habitat for local wildlife
  • Natural texture: Adds authentic wetland character with its grass-like appearance
  • Regional authenticity: If you’re in southern New England, this is genuinely part of your local plant heritage

Growing Conditions and Care

Think marsh and you’ll have the right idea for where this sedge wants to live:

  • Moisture: Consistently moist to wet soil – this plant loves having wet feet
  • Light: Full sun to partial shade work well
  • Soil: Adaptable to various wet soil types, from clay to mucky organic soils
  • Hardiness: Suitable for USDA zones 4-7, perfect for most of New England

Best Uses in the Landscape

This sedge works beautifully in:

  • Rain gardens and bioswales
  • Pond and stream margins
  • Wetland restoration projects
  • Native plant gardens with consistent moisture
  • Wildlife habitat gardens

The Reality Check

Before you get too excited, there’s one catch: finding this sedge for purchase can be challenging since it’s not commonly available in nurseries. Its hybrid nature and limited native range mean it’s more of a specialty plant. You might have better luck contacting native plant societies or wetland restoration specialists in New England.

If you can’t locate Carex ×olneyi, consider some closely related native sedges that are more readily available, such as Carex lacustris or other wetland sedges native to your area.

Growing Tips for Success

If you do manage to get your hands on some Carex ×olneyi:

  • Plant in spring when soil is workable but still consistently moist
  • Don’t let it dry out, especially during establishment
  • Give it space – sedges form clumps that gradually expand
  • Minimal fertilizer needed – these plants are adapted to naturally nutrient-rich wetland soils
  • Cut back old foliage in late winter before new growth emerges

The Bottom Line

Carex ×olneyi is a plant for the dedicated native plant enthusiast who happens to have the right wet conditions and lives in southern New England. It’s not flashy, but it’s authentic, functional, and perfectly suited to wet spots where you want something genuinely local. Just be prepared for a treasure hunt to find it – sometimes the best native plants are worth the extra effort!

Sedge

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Cyperaceae Juss. - Sedge family

Genus

Carex L. - sedge

Species

Carex ×olneyi Boott [bullata × rostrata] - sedge

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