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Pennsylvania Smartweed

Polygonum pensylvanicum

1-25 lbs  $17.40 /lb

26-99 lbs  $16.40 /lb

100+ lbs   $15.40 /lb


Annual forb


1 - 4 feet


Marshy ground


60-80 days


15-20 lbs per acre with approximately 62,000 seeds per lb.

This smartweed grows in a few inches of water and thrives in areas where water recedes in late spring. Smartweed readily reseeds year after year and produces a huge amount of seed which waterfowl love when flooded. It grows best in marshy ground and does not like droughty hard ground or water that is too deep. It can be grown with overhead or flood irrigation. If flooded, the water should be drawn off quickly. The larger the plants, the longer the water may stay on. Smartweed seed is extremely hard. In its wild state, the seed shatters from the plant and, because of its hardness, lays dormant for the winter. During the winter the waterfowl consume some, and most of the rest of the seed breaks dormancy and sprouts as the ground warms and the water over it recedes in the spring. The seed you buy from RRS has been put through a “scarifier” multiple times. The machine scratches the hard seed coat, mechanically breaking dormancy and allowing the seed to be planted in the spring. Even after this process, some seed may not sprout until the following year. Also, unlike wild millet, corn or buckwheat, smartweed may take 2 to 4 weeks to sprout. Matures in 60-80 days.

Planting Instructions: Use general ground prep method (click here).

Spring Planting

Plant after the last chance of frost. Drill 15 – 20 lbs per acre 1/4"-1/2" deep, then roll. For fertilizer, spin spread 200 lbs of 46-0-0 and 50 lbs of 16-16-16. If drilling isn't possible, seed may be spin spread at the rate of 20 – 25 lbs per acre. Apply fertilizer (at the same rate as above), lightly harrow to cover seed and roll if possible.

Fall Planting

Smartweed can also be planted in late fall from late September on in most areas of the country. Use the same methods as above but only use 100 lbs of 16-16-16 fertilizer. The seed will lie dormant for the winter. It can be underwater or in damp ground. If it is underwater, the seed will sprout when the water is removed. It is best to do this near the last frost date. 

Smartweed is a good reseeder and should return year after year. Sometimes a volunteer field will come up too dense, creating too much competition for water and nutrients. When this happens, go through the field with a cultipacker, with teeth down, to thin out the plants. It might look bad at first, but will end up growing into a much better field.

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