How to Grow Pennsylvania Smartweed


The Pennsylvania Smartweed, or Polygonum pensylvanicum, is an annual that grows throughout the United States. It may reach 3 1/2 feet in height, with leaves that are 2 to 6 inches long. The stems are more or less erect but can lean toward the sunlight. Unlike other smartweeds, this plant does not have darker markings on the leaves. Flowers are clustered into spikes at the end of the stems. They are usually pink but can also be white. The Pennsylvania Smartweed is very easy to grow and is an excellent food source for 30 bird species, which eat the seeds.

Step 1

Prepare a planting bed after the last killing frost of the spring. Make sure it is in the full to partial sun. Remove all weeds with weedkiller or handtools.

Step 2

Spread out soil. The plant prefers rich soil, so add fertillizer. Standing water is okay as long as it is temporary.

Step 3

Water the new soil thoroughly. Drop the seeds evenly across the wet bed. Cover with 1 inch of soil

Step 4

Re-flood the area when the plants are at a height of at least 6 inches. During migratory season, flood the area with 12 to 18 inches of water.

Step 5

Replant the seeds every year to ensure they grow uniformly. Smartweed self-sows, so deadhead the plants if you don't want volunteer seedlings to appear.

Things You'll Need

  • Fertilizer


  • Virginia Tech Weed Identification Guide
  • Illinois Wildflowers
  • Dave's Garden
Keywords: Pennsylvania smartweed, weed, Polygonum pensylvanicum

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.