Don Juan roses need to be planted in an area with thorough drainage and full sunlight, according to Garden Guides. They should be fertilized regularly and watered well. In summer, old flowers should be deadheaded and blossom-bearing branches require trimming. During harsh winters, plants should be covered with plastic, and the ground underneath should be mulched.
Don Juan roses are climbing plants that grow up to 10 feet tall and 12 feet wide, so they need to be planted near a weather-resistant structure such as a fence, wall, trellis or arbor so that they have support as they grow. Prepare the rose bed with compost or peat moss up to 12 inches deep to aid with nutrition and drainage. Dig a hole 9 inches to 1 foot deep and about 1.5 feet wide. Add some compost, and after forming a mound in the center of the hole, place the roots of the rose plant over the mound. Gently tamp the soil as the hole is filled, and top the hole with pine bark or organic mulch. During the growing season, keep the soil moist. Be careful, as over-watering causes the lower leaves to become yellow-tinged. Continue watering until the first frost.
According to Today's Garden Ideas, the Don Juan rose is vulnerable to mildew, which looks like white powder on the leaves and buds. Affected parts should be destroyed, and plants should be sprayed with a fungicide. Otherwise, Don Juan roses are hardy, vigorous, easy to grow and wonderfully fragrant.