(Blue Boy Rhododendron, Rhododendron, Watson Hybrid Rhododendron)

Remarkable for both the color and the abundance of its flowers, this hybrid rhododendron bears large spherical clusters of blue-purple flowers in late spring. The ruffled, broadly funnel-shaped blooms have a prominent black-purple blotch on their upper lobes. The upright head-high plants are furnished with long elliptic dark green leaves.

Like most rhododendrons, 'Blue Boy' prefers partial shade and highly organic acid soil that is evenly moist but well-drained. Plant it shallowly and mulch...

(Blue Diamond Rhododendron, Crosfield Hybrid Rhododendron, Rhododendron)

One of the few rhododendrons whose flowers approach blue, this 1939 introduction bears showy spherical clusters of wide-flaring, flat, bright lavender flowers from early to mid-spring. This dense, upright, chest-high shrub has small elliptic dark green leaves that go bronze in winter. It was hybridized by J. J. Crosfield of Embley Park, England.

Like most rhododendrons, 'Blue Diamond' likes chilly winters, moderate summers, and highly organic, well-drained, acid soil. It departs from the norm,...

(Blue Ensign Rhododendron, Rhododendron, Slocock Hybrid Rhododendron)

Offering superior cold hardiness, a dense compact habit, and showy blooms of a shade rarely found among hardy rhododendrons, 'Blue Ensign' bears spherical clusters of lavender-blue, white-centered flowers in mid-spring. The wide-flaring, wavy-edged, funnel-shaped flowers have a purple blotch on their upper lobe. This rounded shoulder-high shrub has large elliptic dark green leaves, which sometimes become spotted. It was raised by W. C. Slocock of Woking, England, patriarch of one of the most prominent...

(Blue Jay Rhododendron, Larson Hybrid Rhododendron, Rhododendron)

H. L. Larson of Tacoma, Washington, developed numerous rhododendron hybrids that are well adapted to the coastal Northwest United States as well as to other areas with relatively mild summers and winters. Most are compact, and many have the beautiful R. degronianum var. yakushimanum in their ancestry. They bear wide-flaring funnel-shaped flowers in large rounded trusses in spring. The red, orange, yellow, pink, purple, or white blooms often have a contrasting blotch on...

(Blue Peter Rhododendron, Rhododendron, Waterer & Crisp Hybrid Rhododendron)

As adaptable as it is beautiful, this broad upright evergreen shrub bears tight spherical clusters of lavender-blue flowers in mid-spring. The ruffled, broadly funnel-shaped blooms have pale throats and a dramatic deep purple blotch. The long elliptic leaves are glossy dark green.

Like most rhododendrons, this vigorous hybrid prefers highly organic acid soil that is evenly moist but well-drained. It departs from the norm, however, in tolerating full sun. Plant it shallowly and mulch well to...

(Bobbink-Atkins Hybrid Azalea)

Developed in the 1940s by Bobbink and Atkins Nursery of East Rutherford, New Jersey, these evergreen azaleas are the result of crosses between Kaempferi and Kurume hybrids and the Japanese native Rhododendron indicum. They bear clusters of funnel-shaped red, pink, orange, or purple flowers on dense upright 4- to 6-foot plants in spring. The funnel-shaped, often ruffled flowers are single or hose-in-hose (with two superimposed sets of petals).

These somewhat cold-tender azaleas prefer...

(Boskoop Hybrid Rhododendron)

The enormous genus Rhododendron comprises more than a thousand species. They are naturally distributed on every continent except Antarctica, Africa and South America. The highest concentrations of species occur in the temperate and mountainous regions of China, Japan, Korea and Taiwan. Grown for their showy flowers, rhododendrons are garden favorites worldwide and have been highly hybridized. There are more than 28,000 registered cultivars.

Plants in this genus are extremely variable...

(Boudoir Azalea, Boudoir Hybrid Azalea, Evergreen Azalea)

Combining superior hardiness, showy mid-spring bloom, and a compact habit, this Gable Hybrid azalea bears clusters of deep rose-pink flowers on rounded chest-high plants. The flaring, wavy-edged, funnel-shaped blooms have red-spotted upper lobes. The small elliptic evergreen leaves are glossy dark green.

Developed mostly by Joseph Gable of Stewartstown, Pennsylvania, Gable Hybrids include some of the hardiest evergreen azaleas available, thanks to the contributions of Rhododendron yedoense...

(Boudoir Hybrid Azalea)

The enormous genus Rhododendron comprises more than a thousand species. They are naturally distributed on every continent except Antarctica, Africa and South America. The highest concentrations of species occur in the temperate and mountainous regions of China, Japan, Korea and Taiwan. Grown for their showy flowers, rhododendrons are garden favorites worldwide and have been highly hybridized. There are more than 28,000 registered cultivars.

Plants in this genus are extremely variable...

(Evergreen Azalea)

Hybrids that have the East Asian species Rhododendron simsii, Rhododendron indicum, and Rhododendron murconatum in their ancestry, the evergreen azaleas in the Indian Group were first developed in the nineteenth century for greenhouse forcing, but have proven to perform well in the landscape in areas where winters are moderate.

These shrubs are grown for their large long-lasting early- to mid-spring flowers on rounded compact plants. The unscented, funnel-shaped, ruffled...