Remove weeds, large rocks, and litter from the planting area. Till the soil 8-10 inches deep and rake several times to break up large clods. It is best to do this when the soil is dry enough to not stick to garden tools. Loosening the soil will help the plant establish strong roots.
Plant 1/8 inch deep in late Fall or early Spring after a killing frost. Mugwort seeds can be directly sown in the garden anytime between late Fall and early-Spring. If sowing after Spring, cold stratification may be needed for seeds to break dormancy and initiate germination. If sowing after Spring, mix the seed with moist sand and store it in the refrigerator for 30 days before direct sowing. Add 1/2" - 3/4" layer of peat moss, sawdust, or potting soil to top of mostly sunny and clear area. Broadcast seeds then water to push seeds into area. Do not work soil too much. Contain growing area to prevent invasive spread.
Watering: Water plants moderately. If the soil moisture is low, water but avoid waterlogging soil.
Weeding: Keep plants free of weeds, which rob weak root systems of nutrients and moisture.
Insecticides: Insecticides may be used to protect plants. Bt-based insecticides and sulfur are organic options that can be used for prevention. Sevin is a synthetic option. Sulfur also has fungicidal properties and helps in controlling many diseases. Before using a pesticide, please read the label and always follow cautions, warnings and directions.
Diseases: Disease can happen in cloudy, damp weather. Check plants daily and treat with an approved fungicide if diseases do appear. Neem oil, sulfur, and other fungicides are available for use. Please always follow label directions.
Harvest mugwort by cutting stalks. Store stalk bundles upside down to dry leaves for tea, herbs, moxibustion, tincture, etc. Harvest or deadhead flowers to prevent invasive spread.