How to Grow Black Cohosh in Oklahoma

Choose a shady location in which to grow the black cohosh.

Amend the soil by pouring three inches of compost on it. Use a gardening fork to combine it with the top six inches of garden soil. If your soil is the heavy, clay variety common in Oklahoma, add three inches of coarse sand and mix it in well. Make sure the soil is well-drained so that the black cohosh can tolerate the amount of rain central and eastern Oklahoma receives in March and April, if you are in those locations.

Cut the black cohosh rhizome into sections that measure three inches in length. There should be at least one bud attached to each piece. If there are any fibrous roots, they should remain attached to the piece.

Dig holes deep enough so that the tops of the rhizomes are covered with two inches of soil. Set the holes 24 inches apart. Plant one rhizome piece in each hole. Make sure that the buds on the rhizome are pointing upwardt. Cover the rhizomes with soil.

Cover the planting area with a three-inch layer of leaf or shredded bark mulch.

Water the area until the top 10 inches of soil are moist and keep the soil moist at all times. Pay close attention to the moisture content of the soil if you live in the panhandle area, as it can dry out quickly there.

Fertilize the black cohosh by applying three to four inches of compost to the soil around the plants every spring. If the plants appears to suffering from a nutrient deficiency, with yellowing leaves or a failure to flower, contact your county's Oklahoma Cooperative Extension agent for recommendations on fertilizers commonly used in your part of the state.