North America Non-native Plant

Callistemon Shiressii

Botanical name: Callistemon shiressii

USDA symbol: CASH9

Native status: Not native but doesn't reproduce and persist in the wild

Synonyms: Callistemon shiresii Blakely, orth. var. (CASH7)   

Callistemon shiressii: The Elusive Bottlebrush If you’ve stumbled across the name Callistemon shiressii in your plant research, you’ve discovered one of the more mysterious members of the beloved bottlebrush family. This Australian native is so rarely documented that even seasoned gardeners and botanists might scratch their heads when they hear ...

Callistemon shiressii: The Elusive Bottlebrush

If you’ve stumbled across the name Callistemon shiressii in your plant research, you’ve discovered one of the more mysterious members of the beloved bottlebrush family. This Australian native is so rarely documented that even seasoned gardeners and botanists might scratch their heads when they hear its name.

What We Know (And Don’t Know)

Callistemon shiressii belongs to the bottlebrush genus, known for their distinctive cylindrical flower spikes that look remarkably like the brushes used to clean bottles. However, this particular species is shrouded in botanical mystery. The plant is also known by the synonym Callistemon shiresii Blakely, which appears to be an alternate spelling of the same plant.

Unfortunately, detailed information about this specific species is remarkably scarce. Unlike its more famous bottlebrush cousins, Callistemon shiressii hasn’t made it into most standard gardening references or plant databases.

Native Status and Distribution

Like other members of the Callistemon genus, this species appears to be native to Australia, though the specific regions where it naturally occurs remain unclear due to limited documentation.

Should You Plant It?

Here’s where things get interesting – and a bit challenging. Given the scarcity of information about Callistemon shiressii, it’s difficult to recommend it for home gardens. We don’t have reliable data about:

  • Its mature size and growth habit
  • Specific growing requirements
  • Hardiness zones
  • Flowering characteristics
  • Wildlife and pollinator benefits

Better Bottlebrush Alternatives

If you’re drawn to the bottlebrush family (and who isn’t?), consider these well-documented alternatives that offer the same Australian charm with much more reliable growing information:

  • Callistemon citrinus (Crimson Bottlebrush) – A reliable performer with bright red flowers
  • Callistemon viminalis (Weeping Bottlebrush) – Graceful drooping branches and abundant blooms
  • Callistemon rigidus (Stiff Bottlebrush) – Compact size perfect for smaller gardens

The Mystery Continues

Sometimes in the plant world, we encounter species that remain tantalizingly out of reach. Callistemon shiressii appears to be one of these botanical enigmas. Whether it’s an extremely rare species, an obsolete name, or simply a plant that hasn’t been thoroughly studied and documented, it reminds us that there’s still much to discover in the world of native plants.

If you’re a plant detective who loves a good mystery, keep an eye out for more information about this elusive bottlebrush. In the meantime, there are plenty of other spectacular Callistemon species waiting to bring their unique beauty to your garden.

Callistemon Shiressii

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

Myrtales

Family

Myrtaceae Juss. - Myrtle family

Genus

Callistemon R. Br. - bottlebrush

Species

Callistemon shiressii Blakely

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