Water your Common rush about once a week during spring and early fall, increasing frequency during hot weather. Plunge your finger into the soil to check for dryness, and water when the top few inches of soil have dried out. It is important to thoroughly water the plant, allowing excess water to drain through the pot or the soil. During the hottest months, you may need to water more than once a week. However, be cautious of overwatering, as it can lead to root rot and other diseases.