Rhododendrons come in many different varieties and have large, leathery evergreen leaves. Rhododendrons bloom during late spring or early summer in show clusters of delicate flowers that are usually pink or purple. Low-growing rhododendrons are most commonly planted as borders or foundation plantings. Some low rhododendron shrubs grow only 2 to 3 feet tall, such as 'Blue Diamond' (Rhododendron intrifact x augustinii). Other low-growing rhododendrons recommended by online resource Landscape Planting Guide, include red-pink bloomed 'Cilpinense' (R. ciliatum x moupinense), light pink 'Bowbells' (R. corona x williamsianum), and 'Moonstone' (R. campylocurpun x williamsianum), with flowers that open pink but become yellow.
Plant your low-growing rhododendrons in well-draining soil and in partial or filtered sunlight, where the shrubs will receive full morning sun and shade in the afternoon. Select a planting site that has some protection from high winds, such as a north- or east-facing slope or beside a building, advised University of Missouri Extension.
Loosen the soil in the planting bed to a depth of 1 1/2 feet using a pitchfork or rototiller. Remove all weeds, grasses and debris from the soil bed.
Dig a planting hole for the rhododendron that's almost twice as wide and the same depth as the root ball or nursery container. Place the rhododendron's root ball into the planting hole and make sure that the top of the root ball is 2 inches higher than the surrounding soil.
Backfill the planting hole with the displaced soil and firm down the soil with your hands. Water the newly-planted rhododendron generously and deeply, soaking the entire area around and beneath the root ball.
Mulch around the rhododendrons. Spread a 2-inch layer of coarse organic mulch, such as wood chips or bark, on the ground around the low-growing rhododendrons to cover the entire root area.
Fertilize the newly-planted rhododendrons lightly if desired, providing about 2 pounds of fertilizer per 100 square feet of bed. Apply a fertilizer made for acid-loving plants and shrubs, according to the directions on the label.
Water your established low-growing rhododendrons deeply and thoroughly once every week or two only during droughts or prolonged dry spells. Don't water the shrubs in September to help them to harden off for winter, but then water the rhododendrons after the first hard, killing frost to keep the soil moist if the fall is dry.
Feed established low rhododendrons in late spring or early summer, after the blooms have faded. Apply a 6-10-4 NPK or similar fertilizer for acid-loving plants at a rate of 2 pound per 100 square feet of plant bed. Don't fertilize the rhododendrons after July 1 to prevent winter injury.
Snap off the flower stems on the low-growing rhododendrons immediately after the flowers fade, leaving the young buds at the flower's base.