North America Native Plant

Island Wallflower

Botanical name: Erysimum insulare insulare

USDA symbol: ERINI5

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Island Wallflower: A Rare California Gem Worth Protecting Meet the island wallflower (Erysimum insulare insulare), a charming yet elusive native perennial that calls California home. This little-known member of the mustard family is one of those plants that makes you feel like you’ve discovered a hidden treasure – mainly because ...

Rare plant alert!

Region: Conservation status by state

Status: S3T2: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Island Wallflower: A Rare California Gem Worth Protecting

Meet the island wallflower (Erysimum insulare insulare), a charming yet elusive native perennial that calls California home. This little-known member of the mustard family is one of those plants that makes you feel like you’ve discovered a hidden treasure – mainly because you kind of have!

A Rare California Native

The island wallflower is a true California native, found exclusively within the Golden State. As its name suggests, this subspecies likely originated from California’s island regions, making it a special piece of the state’s unique botanical heritage. However, here’s the important part: this plant carries a rarity status of S3T2, which means it’s considered rare or uncommon in its natural habitat.

What Makes This Plant Special

Island wallflower is a herbaceous perennial forb, which is just a fancy way of saying it’s a non-woody flowering plant that comes back year after year. Unlike shrubs or trees, it dies back to the ground each winter and emerges fresh each spring, storing its energy in its root system rather than in woody stems.

As a member of the wallflower family, you can expect this plant to produce clusters of small, typically fragrant flowers – though specific details about this subspecies’ appearance and blooming habits are surprisingly scarce in horticultural literature.

Should You Grow Island Wallflower?

Proceed with Caution and Care

Given its rare status, growing island wallflower requires some serious consideration. If you’re interested in adding this plant to your garden, here are the key points to keep in mind:

  • Source Responsibly: Only purchase from reputable native plant nurseries that ethically propagate their stock – never collect from wild populations
  • Limited Availability: Don’t be surprised if this plant is extremely difficult to find in nurseries
  • Conservation Value: Growing rare natives in your garden can help preserve genetic diversity
  • Research Gap: There’s limited specific information available about this subspecies’ growing requirements

Growing Tips (Based on Related Wallflowers)

Since specific growing information for Erysimum insulare insulare is limited, here are some general guidelines based on other California wallflower species:

  • Sun Exposure: Most wallflowers prefer full sun to partial shade
  • Soil: Well-draining soil is typically essential – soggy conditions are usually a no-go
  • Water: Once established, many California natives prefer minimal summer water
  • Climate: Being a California native, it’s likely adapted to Mediterranean-style climates

Garden Design Role

While we don’t have specific information about this plant’s size, growth rate, or exact appearance, wallflowers in general make excellent additions to:

  • Native plant gardens
  • Rock gardens
  • Wildflower meadows
  • Pollinator-friendly landscapes

The Bottom Line

Island wallflower represents both an opportunity and a responsibility. If you can find this rare plant from a reputable source, you’ll be adding a unique piece of California’s natural heritage to your garden while supporting conservation efforts. However, the limited information available means you’ll be somewhat of a pioneer gardener, learning about this plant’s needs through observation and care.

If you’re drawn to the idea of growing rare California natives but want something with more established growing guidelines, consider exploring other native wallflower species or working with local native plant societies to learn more about conservation gardening in your area.

Remember: when it comes to rare plants, every garden that successfully grows them becomes a small sanctuary, helping ensure these botanical treasures don’t disappear from our landscapes forever.

Island Wallflower

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Capparales

Family

Brassicaceae Burnett - Mustard family

Genus

Erysimum L. - wallflower

Species

Erysimum insulare Greene - island wallflower

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