Prairie Thistle

Prairie Thistle (Cirsium canescens) should be watered deeply once or twice a week during the growing season. Water in the early morning and avoid wetting the foliage if possible. Make sure to saturate the ground so that it is moist down to around 6 inches deep. Allow the soil to dry out between waterings. Once the plant is established it can handle some periods of drought. Decrease the frequency of watering in autumn and nearly cease watering in winter.

Prairie Thistle needs full sun to ensure maximum growth, health and productivity. It is best to give the plant at least 6-8 hours of direct sun each day. Try to provide the plant as much sun as possible; the more sun it has, the more flowers and seeds it will produce. If possible, the plant should receive direct sun during the hottest part of the day, which is usually between noon and 3 PM. Additionally, the Prairie Thistle prefers more afternoon sun than morning sun, so that would be best for maximum growth and productivity.

Prairie Thistle (Cirsium canescens) should be pruned after its first flush of flowering. Deadheading, or cutting off its faded flower stalks, encourages new flowers and more vigorous, bushy growth. To promote a neat, compact appearance, young plants can be lightly pruned at the end of the growing season. Stems should be cut back to the base, leaving the rosette of basal foliage undisturbed. Older plants can be more heavily pruned, and the entire plant can be reduced to a few inches tall. This should be done in late winter to early spring to prevent the plant from setting seed. Pruning will help to encourage the plant to flower heavily each year, while removing old stems helps it to remain vigorous.