Nuttall’s thistle is one angry-looking plant. It armed to the proverbial teeth with thin, sharp spines at every angle that seemingly shouy, “Do not touch me, do not munch me. Leave me alone.”
Scientifically known as Cirsium nuttalli, Nuttall’s is one of two thistles native to the Florida Peninsula, the other being purple thistle, Cirsium horridulum. It is, by far, the rarer of the two in South Florida, particularly on the east coast. It’s so rare that the Institute for Regional Conservation classifies it as imperiled.
Nuttall’s range extends throughout the southeastern United States from Virginia south to Florida and west to Texas. Some sources include North Carolina, while others exclude the Tar Heel State. It’s found mainly along the Atlantic and Gulf coastal plains and not so much inland.
In Florida, Nuttall’s is found throughout most of the Peninsula (sans Monroe) and a few counties in the Panhandle.
Nuttall’s is a biennial, meaning it has a two-year life cycle. The first year, it develops a deep tap root and produces a rosette of leaves at its base, but it does not produce any flowers. The second year, it sends up a tall stem, blooms, produces a multitude of fluffy seeds and then croaks.
Nuttall’s is an erect plant, can have a single or multiple stems and multiple branches. It is tall and lanky, reaching five feet or more. The Lady Bird Johnson Wildflower Center at Texas A&M puts Nuttall’s max at a staggeringly tall 11 feet.
Its multitude of branches and flower stems is a key feature that separates Nuttall’s from other thistles, including purple thistle.
The entire plant is heavily armed with sharp spines. Leaves are elliptically shaped and lobed.
What might look like a single flower is actually many small flowers gathered in a single head. They are various shades of pink to a light purple, sometimes white. Nuttall’s blooms spring into fall in South Florida, peaking in mid-summer; in more northerly portions of its range, it blooms in the summer months. The flowers are magnets for a multitude of pollinators, including honey bees, bumble bees and sweat bees, and butterflies. It is a host plant for the little metalmark butterfly and possibly the painted lady butterfly. Birds eat the seeds.
Nuttall’s thistle likes sunny sites with moist soil: pinelands, near marshes, roadsides, ditches, pastures and fallow fields.
Its need for moisture is one reason why Nuttall’s is a difficult plant to cultivate. A second is is those spines. A third is its multitude of fluffy seeds that scatter with the wind; new plants can pop up in great numbers and in unpredictable places. In plain terms, it's weedy.
Like all members of Cirsium, Nuttall’s is edible, roots, stems, leaves and all, spines removed, of course. Many members of Cirsium have been used in traditional medicine, but we could not find uses specific to Nuttall’s.
So who is Nuttall and why is this his thistle? The first answer is Thomas Nuttall, an English naturalist who explored North America during the 19th century. He was the first to scientifically describe this plant but he gave it the binomial name Carduus glaber. Later it was reclassified Cirsium nuttalli.
It is a member of Asteraceae, the sunflower family.
Halpatiokee Regional Park