Rose gardening basics Easy tips for maintaining these fragrant beauties in your garden Watering Build a basin of soil 2 to 6 inches high and 3 feet across. Run the hose in the basin at a slow trickle until the soil is moist but not soggy. Repeat when the top 2 to 3 inches feel dry. Pinterest Fertilizing Wait until after the first bloom to feed new roses. Then water thoroughly so fertilizer won't burn surface roots. Scatter dry fertilizer around the plant, following label instructions; lightly scratch it into the top 1½ inches of soil. Pruning 1. Thin the bush about a month before the last predicted frost to remove dead, old, or weak canes or canes that cross through the center (shown in red) to give the plant an open, vaselike shape.2. Cut remaining canes by less than one-third. Cut at a 45° angle, just above outward-facing buds.