North America Native

Bluntseed Sweetroot

Botanical name: Osmorhiza depauperata

USDA symbol: OSDE

Life cycle: perennial

Habit: forb

Native status: Native to Alaska âš˜ Native to Canada âš˜ Native to the lower 48 states  

Synonyms: Osmorhiza chilensis Hook. & Arn. var. cupressimontana (B. Boivin) B. Boivin (OSCHC)  âš˜  Osmorhiza obtusa (J.M. Coult. & Rose) Fernald (OSOB2)  âš˜  Washingtonia obtusa J.M. Coult. & Rose (WAOB)   

Bluntseed Sweetroot: A Quiet Native for Shade Gardens If you’re looking for a native plant that won’t steal the spotlight but will quietly do its job in your shade garden, meet bluntseed sweetroot (Osmorhiza depauperata). This unassuming perennial might not win any beauty contests, but it’s got some serious native ...

Bluntseed Sweetroot: A Quiet Native for Shade Gardens

If you’re looking for a native plant that won’t steal the spotlight but will quietly do its job in your shade garden, meet bluntseed sweetroot (Osmorhiza depauperata). This unassuming perennial might not win any beauty contests, but it’s got some serious native plant credentials that make it worth considering for the right garden situation.

What is Bluntseed Sweetroot?

Bluntseed sweetroot is a native North American forb – essentially a non-woody perennial herb that dies back to the ground each winter. Standing about 2 feet tall at maturity, this plant produces small white flowers and has coarse-textured green foliage. It’s part of the carrot family, and like many of its relatives, it’s not particularly flashy but serves an important ecological role.

You might also see this plant listed under some synonyms in older references, including Osmorhiza obtusa or Washingtonia obtusa, but Osmorhiza depauperata is the current accepted name.

Native Status and Where It Grows

Here’s where bluntseed sweetroot really shines – it’s impressively native across a massive range of North America. This hardy plant calls home to Alaska, most Canadian provinces, and a whopping number of U.S. states from coast to coast. You’ll find it naturally growing from Alberta to Nova Scotia, and from Arizona to Maine, with stops in between including California, Colorado, Montana, Michigan, and many others.

This incredibly wide native range tells us something important: this is one adaptable plant that has found its niche across diverse climates and conditions.

Why You Might (Or Might Not) Want to Grow It

Reasons to consider bluntseed sweetroot:

  • It’s genuinely native across most of North America
  • Excellent shade tolerance makes it perfect for woodland gardens
  • Provides habitat value as a native species
  • Low maintenance once established
  • Fits well in naturalized, less formal garden settings

Reasons you might pass:

  • Flowers and foliage aren’t particularly showy or ornamental
  • Very slow to establish and spread
  • Limited commercial availability
  • Not drought tolerant, so needs consistent moisture
  • Takes patience – this isn’t an instant gratification plant

Garden Role and Design Uses

Bluntseed sweetroot is what you might call a supporting cast member in the garden world. It’s not going to be your star performer, but it can fill important roles in the right settings. This plant works best in:

  • Woodland and shade gardens where you want native ground cover
  • Naturalized areas that mimic wild forest understory
  • Rain gardens or areas with consistent moisture
  • Native plant collections where you’re focusing on ecological value over ornamental appeal

Think of it as the plant equivalent of a reliable character actor – not the leading lady, but essential for a complete cast.

Growing Conditions

Bluntseed sweetroot has some specific preferences that you’ll need to meet for success:

Light: This plant is shade tolerant, making it perfect for those tricky spots under trees where many plants struggle.

Soil: It adapts well to fine and medium-textured soils but doesn’t love sandy or coarse soils. The pH can range from slightly acidic to slightly alkaline (5.0 to 8.0).

Moisture: Here’s the deal-breaker for some gardeners – bluntseed sweetroot has low drought tolerance and needs medium moisture levels consistently. It’s not the plant for xeriscape gardens or areas where you forget to water.

Climate: Extremely cold hardy (surviving temperatures down to -33°F), this plant can handle harsh winters but needs at least 135 frost-free days to complete its growing cycle.

Planting and Care Tips

Growing bluntseed sweetroot requires patience, but the process is straightforward:

Starting from seed: This is your only real option since the plant isn’t commonly available commercially. Seeds are tiny – you’ll get about 132,000 per pound! Sow them in late spring for summer germination.

Establishment: Be prepared for slow going. This plant has a slow establishment rate and medium seedling vigor, so don’t expect quick results.

Ongoing care: Once established, bluntseed sweetroot is relatively low maintenance. Keep soil consistently moist, and be patient as it slowly spreads (or more accurately, doesn’t spread much at all – vegetative spread is essentially none).

Fertilizing: Medium fertility requirements mean you don’t need to go overboard with fertilizer, but some compost or balanced organic fertilizer can help.

The Bottom Line

Bluntseed sweetroot isn’t going to transform your garden into a showstopper, but if you’re committed to growing native plants and have the right conditions – particularly reliable shade and moisture – it can be a worthy addition to a naturalized woodland garden. Just manage your expectations: this is a plant for native plant enthusiasts rather than ornamental gardeners, and it rewards patience rather than providing instant satisfaction.

If you’re drawn to the idea of growing something truly native to your region but want more immediate visual impact, consider pairing bluntseed sweetroot with showier native companions that share its shade and moisture preferences. Sometimes the best gardens are built on a foundation of quiet, dependable natives like this one.

How

Bluntseed Sweetroot

Grows

Growing season

Spring, Summer, Fall

Lifespan

Moderate

Growth form & shape

Single Crown and Erect

Growth rate

Moderate

Height at 20 years
Maximum height

2.0

Foliage color

Green

Summer foliage density

Porous

Winter foliage density

Porous

Foliage retention

No

Flowering

No

Flower color

White

Fruit/seeds

No

Fruit/seed color

Brown

Allelopath

No

Nitrogen fixing

None

Toxic

None

C:N Ratio

Medium

Fire Resistant

No

Foliage Texture

Coarse

Low-growing Grass

No

Resproutability

No

Coppice Ability

No

Bloat

None

Bluntseed Sweetroot

Growing Conditions

Adapted to Coarse Soil

No

Adapted to Medium Soil

Yes

Adapted to Fine Soil

Yes

Anaerobic tolerance

Low

CaCO₃ tolerance

Medium

Cold Stratification

No

Drought tolerance

Low

Nutrient requirement

Medium

Fire tolerance

Low

Frost-free days minimum

135

Hedge tolerance

None

Moisture requirement

Medium

pH range

5.0 to 8.0

Plants per acre
Precipitation range (in)

14 to 55

Min root depth (in)

10

Salt tolerance

None

Shade tolerance

Tolerant

Min temperature (F)

-33

Cultivating

Bluntseed Sweetroot

Flowering season

Late Spring

Commercial availability

No Known Source

Fruit/seed abundance

Low

Fruit/seed season

Summer to Summer

Fruit/seed persistence

No

Propagated by bare root

No

Propagated by bulb

No

Propagated by container

No

Propagated by corm

No

Propagated by cuttings

No

Propagated by seed

Yes

Propagated by sod

No

Propagated by sprigs

No

Propagated by tubers

No

Seed per pound

132000

Seed spread rate

Slow

Seedling vigor

Medium

Small grain

No

Vegetative spread rate

None

Bluntseed Sweetroot

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

Apiales

Family

Apiaceae Lindl. - Carrot family

Genus

Osmorhiza Raf. - sweetroot

Species

Osmorhiza depauperata Phil. - bluntseed sweetroot

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