How to Protect Mullein

Protect Mullein from freezing temperatures and too much moisture image by jacilluch/


Mullein (Verbascum thapsus) is a biennial with hairy foliage, smooth leaves and densely packed flower clusters at the top of the flowering stem. It is native of Eurasia and was introduced to North America by early settlers. The stems can grow between two and eight feet tall, with flowers that are sulfur yellow in color that bloom from June to September. Mullein is a hardy plant but should still be protected from freezing temperatures and excess moisture to ensure long life.

Step 1

Make sure there is no standing water in the planting bed in order to protect mullein from root rot. The biennial has average moisture needs but should not be kept too wet.

Step 2

Water the plant when the soil is drying out, which should be every two to three days. It should not be over-watered or it may rot and die.

Step 3

Buy mulch such as hay, cedar mulch or straw from a garden store or nursery in the fall. Leaves also work well.

Step 4

Wait until the ground is cold to mulch the planting bed; ideally there should be an inch or two of frost on the ground. This will protect the plants from the alternate freezing and thawing that occurs around wintertime.

Step 5

Make sure the soil is still relatively moist as the ground freezes, to ensure successful winterizing.

Step 6

Add four to six inches of mulch to the crowns of the mullein. This will protect the roots during the extra cold weather.

Tips and Warnings

  • The hairy stems and leaves on mullein can cause contact dermatitis.

Things You'll Need

  • Water
  • Mulch


  • Ohio Perennial and Biennial Weed Guide
  • Missouri Plants
  • Bachmans
Keywords: Mullein, Verbascum thapsus, biennial

About this Author

Based in New York State, Kelly Shetsky started writing in 1999. She is a broadcast journalist-turned Director of Marketing and Public Relations and has experience researching, writing, producing and reporting. She writes for several websites, specializing in gardening, medical, health and fitness, entertainment and travel. Shetsky has a Bachelor of Arts in communications from Marist College.

Photo by: jacilluch/