Gardening Trees, Shrubs & Vines Shrubs How to Plant and Grow Rhododendrons Few plants outshine a rhododendron in full bloom. By Lynn McAlpine Lynn McAlpine Lynn McAlpine is a lifelong gardener and long-time editor of gardening and home articles. Her work encompasses both print publications and online sites. She has hands-on experience with annuals and perennial beds, vegetable gardens, herbs, houseplants, and woodland management. Lynn has a B.A. in Journalism, Magazine Production from the University of Memphis and is a member of ACES, the American Copy Editors Society. Learn about BHG's Editorial Process Updated on December 8, 2022 In This Article View All In This Article Rhododendron or Azalea? Where to Plant Pests and Problems Propagation Types Garden Plans FAQs Close Photo: BHG / Evgeniya Vlasova A classic shade garden plant, rhododendrons are prized for their glossy green foliage and showy clusters of blooms. Available in a variety of hues, the most common flower colors are purples and pinks, as well as white and cream. The Rhododendron genus contains an option for every landscape, from the giant rhododendrons of East Asian mountainsides to the rosebay rhododendrons native to Eastern U.S. woodlands. In areas where dry winters tend to desiccate evergreen types, deciduous varieties of rhododendrons can fill in the gap. Many deciduous types also boast bright yellow and orange hues that work wonders in brightening up shady corners of the garden. When ingested, the leaves, nectar, seeds, and flowers of rhododendrons and azaleas are toxic to humans and pets. Rhododendron Shrub Overview Genus Name Rhododendron Common Name Rhododendron Shrub Plant Type Shrub Light Part Sun, Shade Height 3 to 8 feet Width null to 25 feet Flower Color Orange, Pink, Purple, Red, White, Yellow Foliage Color Blue/Green Season Features Fall Bloom, Spring Bloom, Summer Bloom, Winter Interest Special Features Fragrance, Good for Containers Zones 10, 3, 4, 5, 6, 7, 8, 9 Propagation Layering, Seed, Stem Cuttings Problem Solvers Deer Resistant, Good For Privacy Rhododendron or Azalea? Rhododendrons and azaleas are often confused. Azaleas were once considered a separate genus of plants, but they were reclassified as genetically similar to rhododendrons relatively recently. Now, they are in the same genus. People tend to think of rhododendrons as large evergreen plants with big clusters of blooms and associate azaleas with smaller leaves and shorter plant habits. Where to Plant Rhododendron Rhododendron plants, like many other plants in the Ericaceae family, prefer acidic soils. Many of the evergreen types can be susceptible to burn in winter where they are exposed. To prevent this, plant evergreen types in sheltered areas, avoiding southern exposures where warm, sunny winter days can be fatal. Keep them sheltered from drying winter winds as well. Rhododendron Care Tips Light Most rhododendrons prefer a shade-filled existence, but newer varieties are available for sunny areas as well. Deciduous varieties can hold up much better to more sun. Soil and Water The ideal soil pH for rhododendron plants is somewhere between 4.5 and 6.0. If you have had problems growing rhododendrons in the past, perform a soil test. You can amend the soils with peat moss, compost, and other soil acidifiers to keep them happy. Rhododendrons also appreciate soil that has lots of organic matter. This will keep the shrubs decently moist and prevent them from drying out (dry winters and late falls can be particularly fatal to rhododendrons). On the other end of the spectrum, overly wet soils can also be fatal to rhododendrons. Finding the right balance of moisture in soils can be tricky. Fertilizer Fertilize rhododendrons and azaleas soon after blooming ends. Add a slow-release granular fertilizer to the soil or mulch around the plants. Use a fertilizer especially labeled for rhododendrons or a high-quality compost. Pruning Pruning may be necessary to create a more desirable shape and overall more visually appealing plant. After the plants have bloomed, spent blossoms can be cut back to the new growing tips. After bloom is also the ideal time to do any other pruning. Damaged or diseased growth should always be removed to prevent the spread of disease. You can also do rejuvenation pruning by cutting older plants back more severely to encourage better branching. Pests and Problems Rhododendrons and azaleas are not particularly susceptible to insects, but they sometimes are afflicted by lace bugs, borers, or weevils. Prevent an infestation by choosing resistant species or hybrids that show resistance and by keeping the area around the plant cleaned up. Gardeners who live in areas with a large deer population may have a problem growing rhododendron. Deer love to munch on the leaves of the plant. In these areas, gardeners need to be willing to share, erect fencing or plastic mesh barriers, or use a spray that repels deer. Evergreen types may begin to curl their leaves during the winter. This is a physiological response to dry winter weather. By curling their leaves, they are protecting themselves from cold temperatures and winds to prevent potential winter burn. How to Propagate Rhododendrons The easiest method for a home gardener to propagate a rhododendron or azalea is by layering an existing plant. Weigh a lower branch down until it touches the soil. Cut a slit in the branch where it touches the soil and apply a rooting hormone. A couple of years later, cut the rooted branch to separate it from the parent and transplant it. Another propagation method is by stem cuttings taken from new growth in the early fall. Dip the cuttings in rooting hormone, plant them in a planting medium and keep them in a warm place. Rooting occurs anywhere from 6 weeks to 4 months later. When growing from seeds, sow them indoors in early winter on top of a moist potting soil. Maintain a high humidity, warm environment with no direct sunlight. Transplant the tiny seeding to individual pots. It will be about two years before they can be planted in the ground. Types of Rhododendron With close to 1,000 species in the Rhododendron genus, picking just one is difficult. So don't—pick several instead! Here are some favorites. Encore Autumn Chiffon Azalea Cameron Sadeghpour Rhododendron 'Robled' offers light pink flowers in spring, summer, and fall. It grows 3 feet tall and wide. Zones 7–9 Bloom-A-Thon Rhododendron Justin Hancock A series of semi-evergreen azaleas that feature a re-blooming habit for season-long color. Zones 6–9 'Blue Diamond' Rhododendron Justin Hancock Rhododendron 'Blue Diamond' is a dwarf evergreen rhododendron that bears violet-blue flowers. It grows 5 feet tall and wide. Zones 7–9. Bollywood Rhododendron Justin Hancock Beautiful cream variegated foliage sets this variety apart, with bright magenta flowers in the spring on dwarf plants that make great container plants. It grows 2–3 feet tall and wide. Zones 6–9. 'Capistrano' Rhododendron Jerry Pavia Rhododendron 'Capistrano' is a compact, mounding selection, growing to 4 feet tall and wide, bearing trusses of frilled greenish-yellow flowers. Zones 6–8. 'Cecile' Azalea Todd Dacquisto Rhododendron 'Cecile' grows vigorously to become a dense, 7-foot-tall and 7-foot-wide shrub with trusses of large, salmon-pink flowers. Zones 5–8. 'Hydon Dawn' Rhododendron Andrew Drake Rhododendron 'Hydon Dawn' is one of the few rhododendrons that tolerates full sun. It has a low, compact growing habit of 5 feet tall and wide and bears clusters of small, clear pink flowers that fade to white. Zones 7–9. 'Fielder's White' Azalea Denny Schrock Rhododendron 'Fielder's White' is blanketed with single white blossoms in mid-spring. Evergreen foliage complements the 3-inch-wide flowers on this variety. Zones 8–9. 'Gibraltar' Azalea BHG / Evgeniya Vlasova Rhododendron 'Gibraltar' grows vigorously to 5 feet tall and wide, bearing bright orange flowers. Can tolerate full sun. Zones 5–8. 'Karen' Azalea Bob Stefko Rhododendron 'Karen' is a hardy evergreen azalea bearing purple flowers in spring. It grows 3 feet tall and wide. Zones 4–9. 'Mandarin Lights' Rhododendron Dean Schoeppner A deciduous type of azalea, it features bright orange blooms in spring on naked stems before the foliage emerges. It tops out around 4–5 feet tall. Zones 3–7. 'Purple Dragon' Azalea Denny Schrock Rhododendron 'Purple Dragon' features striking dark purple-red flowers that open at the branch tips in late spring. The shrub grows 3–4 feet tall and wide. Zones 7–9. 'Hino Crimson' Azalea BHG / Evgeniya Vlasova Rhododendron 'Hino Crimson' is a dwarf, densely growing azalea that produces bright red flowers. It grows 2 feet tall and wide. Zones 5–8. Korean Azalea Sherry Lubic Rhododendron yedoense poukhanense bears lilac to deep-rose funnel-shaped flowers in spring. In fall, leaves change to a gold or reddish purple. It grows 6 feet tall and wide. Zones 5–9 'Nova Zembla' Rhododendron Lynn Karlin Rhododendron 'Nova Zembla' is a large evergreen shrub that bears trusses of deep red flowers with spotted throats. It grows 5 to 10 feet tall and wide. Zones 5–8. 'Nuccio's Carnival' Azalea Denny Schrock Rhododendron 'Nuccio's Carnival' presents a profusion of large, single to semi-double magenta blossoms that add a burst of color to the landscape. Flowers are backed by rich green evergreen foliage. Zones 8–9. 'Olga Mezitt' Rhododendron Lynn Karlin Rhododendron 'Olga Mezitt' is an evergreen selection that produces small trusses of deep peach-pink flowers. The leaves redden in fall. It grows to 4 feet tall and wide. Zones 4–8. 'Rose Queen' Azalea Denny Schrock Rhododendron 'Rose Queen', a cotton candy-pink cultivar, has ruffled flowers in mid-spring. It grows 4-6 feet tall and wide. Zones 8–10. 'Sun Chariot' Rhododendron Helen Norman Photography Rhododendron 'Sun Chariot' is an upright, dense-growing spring-blooming variety that grows 6 feet tall and wide. It bears yellow blooms with orange blotches in large clusters. Zones 6–9. 'Trude Webster' Rhododendron Mary Carolyn Pindar Rhododendron 'Trude Webster' forms a compact, upright plant with clustered, clear pink flowers. It grows 5 feet tall and wide. Zones 6–9. Garden Plans for Rhododendrons Foundation Garden Illustration by Mavis Augustine Torke A colorful alternative to the standard all-green landscape, this foundation planting mixes broad-leafed evergreen shrubs and a sculptural tree with flowering perennials and groundcovers. Download This Garden Plan! Year-Round Excitement Garden Plan Janet Loughrey Creating a garden around foliage is a surefire way to produce multiseason interest. While most garden beds focus on flowers, this mixed border emphasizes foliage plants of varying heights and textures, and throws flowers in for interest. Click here to get this plan! Frequently Asked Questions Should I mulch rhododendrons and azaleas? In the spring, mulch the plants with up to 5 inches of pine bark chips or pine needles to retain moisture. However, don’t pile the mulch around the base and trunk of the shrub. It encourages rot. Leave a few inches around the plant base free of mulch. How long do rhododendrons live? Most rhododendrons can live anywhere from 10 years to decades, depending on the care they receive. A few specimens have made it past 100! Was this page helpful? Thanks for your feedback! Tell us why! Other Submit