Thistle
44 images Created 24 May 2015
Thistles are common in the Texas landscape - in fact they have a real Texas look about them: colorful, spiny and able to live through about anything. But those who look like cousins may not be. I searched through the Native Plant Database, looking for the very common Nodding Thistle featured here. Finally, the story came together - it is an invasive Old World plant, not a native.
Other plant varieties on the following pages, like the Texas Thistle and Yellow Thistle are native. Though native, the American Star Thistle, or Basket Flower - scientifically speaking - is not really a Thistle. As usual, the botany gets complex, even for flowers you see along the roadsides and fence lines that look similiar.
Cirsium texanum
A native biennial, the Texas Thistle produces single bright flowers on top of stems two to five feet tall. It has a distinct green ‘vase’ from which the flower explodes. Drought tolerant, it blooms from April into August. It is a favorite of bumblebees, birds and butterflies and it’s seeds are popular with Goldfinches.
Cirsiuim horridulum
The Yellow Thistle is a most fearsome plant, spiny from top to bottom, yet with the most delicate flower head that emerges from the spine-protected buds. It can grow from one to more than five feet tall in dense stands that can dominate overworked pastures. It can spread rapidly and has a deep, tenacious root. Cattle stay clear, while butterflies enjoy it. It plays host for the larva of the Little Metalmark butterfly.
Carduus nutans
The Nodding Thistle is nonnative and spreading widely along Texas roadsides. It is a favorite of butterflies and bees, but can be a problem in depleted pastures. Ranchers hate this invasive species. It can grow in such dense stands that only snakes and insects seem to penetrate. The plants grow up to six feet tall with flower heads two or three inches across. A biennial, it flowers from May through July.
Other plant varieties on the following pages, like the Texas Thistle and Yellow Thistle are native. Though native, the American Star Thistle, or Basket Flower - scientifically speaking - is not really a Thistle. As usual, the botany gets complex, even for flowers you see along the roadsides and fence lines that look similiar.
Cirsium texanum
A native biennial, the Texas Thistle produces single bright flowers on top of stems two to five feet tall. It has a distinct green ‘vase’ from which the flower explodes. Drought tolerant, it blooms from April into August. It is a favorite of bumblebees, birds and butterflies and it’s seeds are popular with Goldfinches.
Cirsiuim horridulum
The Yellow Thistle is a most fearsome plant, spiny from top to bottom, yet with the most delicate flower head that emerges from the spine-protected buds. It can grow from one to more than five feet tall in dense stands that can dominate overworked pastures. It can spread rapidly and has a deep, tenacious root. Cattle stay clear, while butterflies enjoy it. It plays host for the larva of the Little Metalmark butterfly.
Carduus nutans
The Nodding Thistle is nonnative and spreading widely along Texas roadsides. It is a favorite of butterflies and bees, but can be a problem in depleted pastures. Ranchers hate this invasive species. It can grow in such dense stands that only snakes and insects seem to penetrate. The plants grow up to six feet tall with flower heads two or three inches across. A biennial, it flowers from May through July.
