Native Thistles

I want to introduce you to some misunderstood plants.

Most of us think of thistles as weeds – most of the ones we see along roadsides and field edges are not native and very aggressive.   But there are several native thistles that are well behaved, and will even grow well in gardens.  I’ve planted three species of native thistles in our prairie meadow.  One of them is blooming right now.

Field Thistle is a very tall biennial.  The first year it produces only leaves in a rosette close to the ground; the second year it grows a tall flowering stalk, and then dies after it flowers and goes to seed.

Here it is blooming in the Prairie Meadow on August 20, 2013.

Cirsium discolor

 

Here are the other two thistles I planted in the prairie meadow.  Neither has bloomed  yet, so these photos are from our farm.

Swamp Thistle

swamp thistle

 

Swamp Thistle in our wetland at the farm

cirsium muticum in wetland 2005

 

Tall Thistle – This is a REALLY tall thistle – sometimes as much as 10 feet tall.  It grows in shady woods or woods edges.

cirsium altissimum small

 

It’s hard to get a photo of what the whole plant looks like because it’s so tall, but here’s one that’s about 7 feet tall.

tall thistle

 

All kinds of insects nectar on thistle flowers.  Here are a few examples.

Bumble bees, Soldier Beetles, and other unknown beetles on Field Thistle

thistle with insects

 

Giant Swallowtail Butterfly on Field Thistle

giant swallowtail on thistle 3

 

Monarch Butterfly and Fritillary Butterfly on Field Thistle

monarch and fritillary on thistle

 

Painted Lady Butterflies lay their eggs on thistles, and their caterpillars eat the leaves.  The caterpillars build a ‘nest’ of silk along the stem and retreat into it for protection.  This is a Painted Lady caterpillar nest on Field Thistle.

painted lady caterpillar on thistle

 

Here’s a photo of an adult Painted Lady butterfly.

Painted Lady

 

Goldfinches also use thistles.  Unlike many songbirds, Goldfinches don’t start nesting right away in the spring.  They time their nesting to coincide with the maturing of the thistle seed heads.  They eat the seeds and use the seed fluff to line their nests.

Thistle fluff

thistle fluff

 

Goldfinch nest lined with thistle fluff

goldfinch nest

So please take a new look at thistles, and enjoy the ones that are blooming in our prairie meadow.  If you visit the flowers during the day, you’ll probably be able to watch some birds or insects visiting them.

Marcie O’Connor
August 22, 2013