Native Plants

Tansy Rosinweed

Silphium pinnatifidum

USDA symbol: SIPI2

perennial forb

Lower 48 states: native

If you’re looking for a native wildflower that makes a bold statement in your garden, tansy rosinweed (Silphium pinnatifidum) might just be your new favorite plant. This impressive perennial forb brings sunshine-yellow blooms and architectural beauty to landscapes across the southeastern and south-central United States. But fair warning – this ...

Tansy Rosinweed may be listed as rare in your area.
Global Conservation Status

Status: S3Q | Vulnerable: Found only in a restricted range (even if abundant at some locations). Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals.

Tansy Rosinweed: A Towering Native Wildflower Worth the Wait

If you’re looking for a native wildflower that makes a bold statement in your garden, tansy rosinweed (Silphium pinnatifidum) might just be your new favorite plant. This impressive perennial forb brings sunshine-yellow blooms and architectural beauty to landscapes across the southeastern and south-central United States. But fair warning – this plant requires patience and the right conditions to truly shine.

What Makes Tansy Rosinweed Special

Tansy rosinweed stands out from other native wildflowers with its distinctive deeply divided leaves that give it the pinnatifidum part of its scientific name (which literally means pinnately cut). The plant produces large, bright yellow composite flowers that look remarkably similar to sunflowers, creating a spectacular display in late summer and fall when many other blooms are fading.

As a native perennial forb, this plant lacks woody stems but develops an impressive deep taproot system that helps it survive drought conditions. Don’t let the term forb fool you – this wildflower can reach impressive heights and create real visual impact in the right setting.

Where Tansy Rosinweed Calls Home

This native beauty naturally occurs across several states including Alabama, Georgia, Illinois, Indiana, Kentucky, Tennessee, and Wisconsin. It’s perfectly adapted to the climate and growing conditions of these regions, making it an excellent choice for gardeners wanting to support local ecosystems.

  • Species observed
  • No observations

A Note About Conservation

Tansy rosinweed has an undefined conservation status, which means we don’t have complete information about its population stability in the wild. If you decide to add this plant to your garden, make sure you source it responsibly from reputable native plant nurseries rather than collecting from wild populations.

Garden Design and Landscape Use

This tall wildflower works beautifully in several garden settings:

  • Back borders of perennial beds where its height won’t overshadow shorter plants
  • Prairie and meadow gardens where it can naturalize
  • Native plant gardens focused on regional species
  • Pollinator gardens where its late-season blooms provide crucial nectar
  • Cottage-style gardens for a relaxed, naturalistic feel

Growing Conditions and Care

Tansy rosinweed thrives in USDA hardiness zones 4-8, making it suitable for a wide range of climates. Here’s what this native wildflower needs to succeed:

Sunlight: Full sun is essential – this plant won’t perform well in shady conditions.

Soil: Well-draining soil is crucial. Once established, the deep taproot makes it quite drought tolerant, so avoid overly wet or poorly draining areas.

Water: Average to dry conditions work best. Overwatering can actually harm this plant.

Planting and Establishment Tips

Growing tansy rosinweed successfully requires understanding its growth pattern and needs:

  • Start from seed rather than transplants when possible – the taproot doesn’t like disturbance
  • Direct sow seeds in fall for natural cold stratification
  • If starting indoors, seeds need cold stratification treatment
  • Be patient – this plant is notoriously slow to establish, sometimes taking 2-3 years to reach maturity
  • Once established, it’s quite low-maintenance and long-lived

Wildlife and Pollinator Benefits

The late summer and fall blooming period makes tansy rosinweed particularly valuable for pollinators preparing for winter. Butterflies, native bees, and other beneficial insects appreciate these bright yellow flowers when many other nectar sources have finished for the season.

Is Tansy Rosinweed Right for Your Garden?

This native wildflower is perfect for gardeners who:

  • Want to support native ecosystems and pollinators
  • Have patience for slow-establishing plants
  • Prefer low-maintenance, drought-tolerant options
  • Need tall plants for back borders or prairie plantings
  • Live within its native range

However, you might want to consider other options if you need quick results, have limited space, or frequently rearrange your garden beds.

Tansy rosinweed rewards patient gardeners with years of striking late-season color and the satisfaction of growing a plant that truly belongs in your local landscape. Just remember to source it responsibly and give it the sunny, well-drained conditions it craves.

Silphium pinnatifidum 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. Silphium pinnatifidum is also known as:

Silphium chickamaugense | USDA symbol: SICH3
Silphium terebinthinaceum var. pinnatifidum | USDA symbol: SITEP

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.

Classification

Group: Dicot
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Asteridae
Order: Asterales
Family: Asteraceae Bercht. & J. Presl - Aster family
Genus: Silphium L. - rosinweed

Species: Silphium pinnatifidum Elliott - tansy rosinweed

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