North America Native Plant

Henson’s Calammophila

Botanical name: ×Calammophila donhensonii

USDA symbol: CADO7

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Henson’s Calammophila: Michigan’s Mysterious Hybrid Grass Meet one of North America’s botanical enigmas: Henson’s calammophila (×Calammophila donhensonii). This isn’t your typical garden grass recommendation – in fact, it’s quite the opposite. This rare hybrid represents one of nature’s fascinating experiments in plant evolution, and it comes with a story that’s ...

Henson’s Calammophila: Michigan’s Mysterious Hybrid Grass

Meet one of North America’s botanical enigmas: Henson’s calammophila (×Calammophila donhensonii). This isn’t your typical garden grass recommendation – in fact, it’s quite the opposite. This rare hybrid represents one of nature’s fascinating experiments in plant evolution, and it comes with a story that’s more about conservation than cultivation.

What Makes This Grass Special?

The × symbol in front of Calammophila immediately tells us something important: this is a hybrid species, meaning it arose from the natural crossing of two different parent species. Henson’s calammophila is a perennial grass that belongs to the diverse world of graminoids – the technical term for grasses and grass-like plants including true grasses, sedges, and rushes.

Where in the World Can You Find It?

Here’s where things get really interesting (and a bit sad from a biodiversity perspective). Henson’s calammophila is native to the United States, but its distribution is incredibly limited – it’s only been documented in Michigan. This makes it one of the rarest grass species in North America.

Why You Won’t Find This in Your Local Nursery

Before you start searching for seeds or plants online, let’s set expectations: Henson’s calammophila is not available for home cultivation, and for good reason. Its extreme rarity means that:

  • It’s not propagated commercially
  • Wild collection would be ecologically harmful
  • Its specific growing requirements are largely unknown
  • It may require very particular environmental conditions found only in its native Michigan habitat

The Conservation Story

This grass represents something much more valuable than a garden specimen – it’s a piece of our natural heritage that needs protection. Hybrid species like this one often occupy very specific ecological niches and can be incredibly sensitive to environmental changes. Climate change, habitat loss, and human disturbance pose significant threats to such rare species.

What This Means for Native Plant Gardeners

While you can’t grow Henson’s calammophila in your garden, its existence reminds us of the incredible diversity of native plants that once covered our landscapes. Instead of seeking out this rare hybrid, consider these alternatives:

  • Plant other native Michigan grasses that are readily available
  • Support conservation organizations working to protect rare plant habitats
  • Create habitat corridors in your landscape using locally appropriate native species
  • Learn about and advocate for the protection of rare plants in your area

The Bigger Picture

Henson’s calammophila serves as a perfect example of why native plant conservation matters. Every rare species represents thousands of years of evolutionary adaptation to specific conditions. When we lose these plants, we lose irreplaceable genetic diversity and ecological relationships.

While this grass won’t be gracing your garden anytime soon, its story highlights the importance of protecting the wild spaces where such botanical treasures can continue to exist. Sometimes the best thing we can do for a plant is simply to let it be, safely thriving in its natural habitat.

So next time you’re planning your native plant garden, remember Henson’s calammophila – not as something to grow, but as inspiration to choose native plants that support your local ecosystem while leaving the rarest treasures undisturbed in the wild where they belong.

Henson’s Calammophila

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

Poaceae Barnhart - Grass family

Genus

×Calammophila Brand - calammophila

Species

×Calammophila don-hensonii Reznicek & E.J. Judziewicz [Ammophila breviligulata × Calamagrostis canadensis] - Henson's calammophila

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