How to Grow Scottish Thistle


Scottish thistle, native to and beloved in Scotland, is a thorny biennial plant with tall stems and purple flowers on top. People unfamiliar with the flower often mistake them for weeds, and in the United States, they are often classified as an invasive weed. To keep Scottish thistle in check, keep your plant count low. They grow best in hardiness zones 5 to 8, the areas where temperatures do not drop below negative 20 degrees F (See Resources).

Step 1

Plant the Scottish thistle plant or seeds in early spring in well-drained soil where it will get part to full sun. Once established, the thistle can thrive in dry, gravelly soil and full, harsh sun.

Step 2

Water the plant, keeping it moist until it becomes established. Once it starts growing vigorously, decrease the amount of watering, allowing the soil to dry in between and eventually tapering off completely. When firmly established, the thistle can survive and thrive on natural rainwater.

Step 3

Cut spent flowers carefully with clippers once or twice per week during the summer, putting on thick gloves before touching the plant. Put the flowers in a container to be thrown away or burned later.

Step 4

Cut down the plant after it has finished flowering, as it will only flower once in the second year of a biennial cycle. Cut it down in sections, taking care not to drop any part of the plant onto the ground. Replace the old plant with a new one.

Tips and Warnings

  • Do not drop any flowers or put them in your compost pile as the plant seeds can live for 20 years in the ground, and once out of control, the plant will spread quickly.

Things You'll Need

  • Thistle plant or seed
  • Water
  • Pruning clippers
  • Container


  • University of Maryland Cooperative Extension PDF: Beware Beloved Scottish Thistle

Who Can Help

  • Arbor Day Foundation: Hardiness Zone Map
Keywords: growing Scottish thistle, controlling Scottish thistle, caring for Scottish thistle

About this Author

Sarah Morse recently graduated with a Bachelor of Arts in English language and literature. She has been freelancing for three months and got her start writing for an environmental website.

Article provided by eHow Home & Garden | How to Grow Scottish Thistle