Content Detail

This is a hardy series of azalea hybrids (Rhododendron) which were developed in Minnesota for bud hardiness. They can withstand temperatures as low as -35° F without significant damage. Azaleas are deciduous (drop their leaves in fall), and have five stamens in each flower. They should be sited in a protected area in a well-drained soil. Numerous flower colors are available.

  • Family (English) Heath
  • Family (botanic) Ericaceae
  • Tree or plant type Shrub
  • Foliage Deciduous (seasonally loses leaves)
  • Native locale Non-native
  • Size range Low-growing shrub (under 3 feet), Small shrub (3-5 feet), Medium shrub (5-8 feet)
  • Light exposure Full sun (6 hrs direct light daily), Partial sun / shade (4-6 hrs light daily)
  • Hardiness zones Zone 3, Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7
  • Soil preference Acid soil, Moist, well-drained soil
  • Tolerances Occasional drought
  • Season of interest mid spring, late spring, early summer
  • Flower color and fragrance Fragrant, Orange, Pink, Purple, Red, White, Yellow
  • Shape or form Oval, Round, Upright
  • Growth rate Moderate

Size and form:

Rhododendron Northern Lights™ Series is a cross between Mollis hybrid azalea (R. kosteranum) and Roseshell rhododendron (R. prinophyllum). Most are upright to rounded in habit, reaching 3 to 4 feet high.

Native geographic location and habitat:

These plants are of hybrid origin.

Attracts birds, pollinators, or wildlife:

Butterflies and bees are attracted to azaleas.

Bark color and texture:

The stems are slender and straw-brown in color.

Leaf or needle arrangement, size, shape, and texture:

The leaves are alternate, deciduous, elliptical to lanceolate, 1 to 3 inches long and  thin textured. They are medium green, turning a bronzy-purple fall color.

Flower arrangement, shape, and size:

Flowers clusters (trusses) of up to 12 flowers appear before the leaves emerge in spring. Each fragrant flower is tubular, five-petaled and fused near the center. They are available in many colors.

Fruit, cone, nut, and seed descriptions:

This series of azaleas is sterile, so no seed capsule is produced.

Plant care: 

Azaleas have fine, shallow root systems, so a well-drained soil is a must. Ideally, the soil should be rich in organic matter. The plants prefer acid soil (5.0-6.0 pH). It can be grown in full sun in a protected site, but it does best in part shade. Prune lightly to remove dead wood and promote bushier growth.

List of pests, diseases, and tolerances:

If the soil is  too alkaline, the leaves will develop chlorosis. Leaf spots, lacewings, leaf galls, and root rots (in wet soil) can be problems on this plant. It is susceptible to black walnut toxicity and should not be planted under black walnut trees. 


Candy Lights Azalea (Rhododendron ‘Candy Lights’):

This azalea has lavender-purple flowers and is 3 to 4 feet high and wide.

Golden Lights Azalea (Rhododendron ‘Golden Lights’):

This 1986 introduction has golden yellow flowers which are 2 inches across. The plant is 4 feet high and wide. 

Mandarin Lights Azalea (Rhododendron ‘Mandarin Lights’):

This plant has mandarin orange flowers and is 4 to 5 feet high and wide.

Northern Hi-lights Azalea (Rhododendron ‘Northern Hi-lights’):

A 1994 introduction with creamy white flowers with bright yellow upper petals. It is 4 to 5 feet high and wide.

Orchid Lights Azalea (Rhododendron ‘Orchid Lights’):

  A 1986 introduction with orchid-colored flowers. It is 3 to 4 feet high and wide.

Pink Lights Azalea (Rhododendron ‘Pink Lights’):

The flowers are light pink and highly fragrant. It is 8 feet high and wide. It was introduced in 1984.

Rosy Lights Azalea (Rhododendron ‘Rosy Lights’):

The deep rose colored flowers are highly fragrant. It reaches 8 feet high and wide. It was introduced in 1984.

Spicy Lights Azalea (Rhododendron ‘Spicy Lights’):

This plant has salmon colored flowers that are slightly fragrant. It reaches 6 feet high and 8 feet wide.

White Lights Azalea (Rhododendron ‘White Lights’):

The pink buds open to white flowers with a yellow blotch. The flowers are very fragrant. The plant is 5 feet high and wide.


Your support is vital to the Arboretum, where the power of trees makes a positive impact on people’s lives.

Make a gift