Moana Nursery High Desert Plant Finder & Guide
shrub

Grandiflorum Rhododendron

Rhododendron catawbiense 'Grandiflorum'

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Grandiflorum Rhododendron (Rhododendron catawbiense 'Grandiflorum') at Moana Nursery

Grandiflorum Rhododendron flowers

Grandiflorum Rhododendron flowers

(Photo courtesy of NetPS Plant Finder)

Grandiflorum Rhododendron (Rhododendron catawbiense 'Grandiflorum') at Moana Nursery

Grandiflorum Rhododendron in bloom

Grandiflorum Rhododendron in bloom

(Photo courtesy of NetPS Plant Finder)

Height:  8 feet

Spread:  7 feet

Sunlight:  partial shade 

Hardiness Zone:  4

Other Names:  Catawba Rhododendron

Description:

An attractive broadleaf evergreen shrub with cheerful lavender flowers with tan spots; blooms in mid spring and has a compact upright habit, quite hardy, good in partial shade; absolutely must have well-drained, highly acidic and organic soil

Ornamental Features

Grandiflorum Rhododendron is smothered in stunning clusters of lilac purple trumpet-shaped flowers with rose overtones and tan spots at the ends of the branches in mid spring, which emerge from distinctive purple flower buds. It has green evergreen foliage. The narrow leaves remain green throughout the winter.

Landscape Attributes

Grandiflorum Rhododendron is a multi-stemmed evergreen shrub with an upright spreading habit of growth. Its relatively coarse texture can be used to stand it apart from other landscape plants with finer foliage.

This is a relatively low maintenance shrub, and should only be pruned after flowering to avoid removing any of the current season's flowers. It has no significant negative characteristics.

Grandiflorum Rhododendron is recommended for the following landscape applications;

  • Accent
  • Mass Planting
  • General Garden Use

Planting & Growing

Grandiflorum Rhododendron will grow to be about 8 feet tall at maturity, with a spread of 7 feet. It tends to be a little leggy, with a typical clearance of 1 foot from the ground, and is suitable for planting under power lines. It grows at a slow rate, and under ideal conditions can be expected to live for 40 years or more.

This shrub does best in a location that gets morning sunlight but is shaded from the hot afternoon sun, although it will also grow in partial shade. Keep it away from hot, dry locations that receive direct afternoon sun or which get reflected sunlight, such as against the south side of a white wall. It requires an evenly moist well-drained soil for optimal growth, but will die in standing water. It may require supplemental watering during periods of drought or extended heat. It is very fussy about its soil conditions and must have rich, acidic soils to ensure success, and is subject to chlorosis (yellowing) of the foliage in alkaline soils. It is somewhat tolerant of urban pollution, and will benefit from being planted in a relatively sheltered location. Consider applying a thick mulch around the root zone in winter to protect it in exposed locations or colder microclimates. This is a selection of a native North American species.

 
 
Hardiness Zone Plant Height Minimum Sunlight Soil pH Preference
Characteristics
Accent  Massing  Garden 
Applications
Flowers  Winter Value 
Ornamental Features