Rhododendron 'Rhodunter 48' SCENT-SATIONAL WHITE

Common Name: rhododendron 
Type: Broadleaf evergreen
Family: Ericaceae
Zone: 5 to 8
Height: 6.00 to 7.00 feet
Spread: 6.00 to 7.00 feet
Bloom Time: May
Bloom Description: White
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Hedge
Flower: Showy, Fragrant
Leaf: Evergreen
Attracts: Hummingbirds, Butterflies
Other: Winter Interest
Tolerate: Rabbit


Best grown in acidic, organically rich, humusy, medium moisture, moisture-retentive but well-drained soils in part shade. Prefers a sun dappled or high open shade. Morning sun with afternoon shade is also acceptable. Tolerates a fair amount of sun in cool northern summers, but leaves may scorch in hot afternoon sun in the St. Louis area. Plant in a location protected from strong winds. Plants perform well on north or east facing slopes. Do not site plants within or near the drip line of trees in the walnut family (most rhododendrons/azaleas are sensitive to toxic juglones produced by roots of walnuts, butternuts, pecans and hickories). Good soil drainage is essential (plants do not like “wet feet”). Poor drainage inevitably leads to root rot, therefore raised beds/plantings should be considered in heavy clay soils such as those present in much of the St. Louis area. Shallow, fibrous root systems (do not cultivate around plants) will benefit greatly from a mulch (e.g., wood chips, bark or pine needles) to help retain moisture and stabilize soil temperatures. Roots must never be allowed to dry out. Acidify soils as needed (plants generally like soil pH in the range of 5.0 to 5.5). Add sulfur or iron sulfate to soils to lower the pH. Add limestone or lime to soils to raise the pH. Clip off spent flower clusters immediately after bloom as practicable.

'Rhodunter 48' is tolerant of a wider range of soil types than other rhododendrons, decreasing the need for soil amendments. It can be grown in acid, lime, and heavy clay and loam soils up to pH 7.

Noteworthy Characteristics

Rhododendron is a genus of 500 to 900 species and includes both of what we commonly call rhododendrons and azaleas. Most are evergreen but some are deciduous. They originate mostly from the Northern Hemisphere with high concentrations in western China, the Himalayas and Myanmar (Burma). They are grown for their showy spring flowers and in the case of evergreen types for their attractive winter foliage. True rhododendrons have 10 stamens in a flower and azaleas have only 5. Much hybridization has resulted in a great number of hybrid cultivars. Of note to gardeners in cool temperate areas are the large and small leaved evergreen rhododendrons and the evergreen and deciduous azaleas.

The evergreen rhododendrons produce large to small, linear leaves that are stiff and evergreen. They usually branch from a central trunk unlike the evergreen and deciduous azalea that are multi-stemmed from the ground. Large trusses of flowers are produced at the tips of branches followed by a flush of new leaves. Colors range from white to pink, red, and purple. Size can range from 1-2 feet to over 15 feet tall depending upon the cultivar.

Genus name comes from the Greek words rhodo meaning rose and dendron meaning tree. Transferred from the Greek name for Nerium oleander.

INKARHO® rhododendrons were created by breeders in a planned breeding program in Germany to develop rhododendrons more tolerant of higher pH soils. To date, five “lime-tolerant” Rhododendron rootstocks from this program have been patented in the U.S. (‘Rhodunter 10’, ‘Rhodunter 37’, ‘Rhodunter 48’, ‘Rhodunter 149’, ‘Rhodunter 150’). INKARHO rhododendrons, for the most part, are named cultivars grafted onto one of these rootstocks though some also are the rootstock plants grown on their own. (The name INKARHO stands for INter-essengemeinschaft KAlktoleranter RHOdo-dendron or lime-tolerant rhododendron.)

‘Rhodunter 48’ commonly sold under the trade name of SCENT-SATIONAL WHITE, is part of the INKARHO series. It typically matures to 6-7’ tall and as wide and features oblanceolate evergreen leaves (to 8” long), and fragrant widely funnel-shaped white flowers with yellow throats. Flowers blooms in trusses in May. U.S. Plant Patent PP15,967 was issued on September 20, 2005.


Rhododendrons and azaleas are susceptible to many insect and disease problems. Insect pests include aphids, borers, lacebugs, caterpillars, leafhoppers, mealybugs, nematodes, scale, thrips and whitefly. Mites may also appear. Disease pests include blights, canker, crown rot, leaf gall, root rot, leaf spot, rust and powdery mildew. Chlorosis (leaves turn yellow) often indicates an iron deficiency in the soil that is often caused when the soil pH becomes too high. A healthy plant in the proper environment with proper care should have limited problems, however.


Mass, group or specimen. Shrub borders, mixed borders, woodland gardens and shade gardens. Also effective in foundation plantings or as a hedge. Woodland margins.