Habitat

• zone 4
• group of hybrids resulting from a cross between R. carolinianum and R. dauricum var. sempervirens
• named after Peter J. Mezitt, founder of Weston Nurseries, Massachusetts

Habit and Form

• compact with a mounded, neat appearance
• foliage covering is dense
• landscape plants typically 4' to 6' tall, but can grow to 10' with a width about two-thirds the height
• evergreen, small-leaved rhododendron

Summer Foliage

• small evergreen leaves
• 1" to 2.5" long
• elliptical shape
• alternate leaf arrangement
• aromatic when leaves are bruised/crushed
• dark speckling on underside of scales
• dark green, somewhat shiny foliage

Autumn Foliage

• evergreen leaves turn a wonderful deep mahogany-purple in winter
• more sun exposure creates more winter foliage color

Flowers

• blooms in mid to late April
• flower color is a vivid, potent lavender-pink
• exact color varies with the particular selection of 'PJM'
• generally blooms heavily and reliably

Fruit

• generally does not set seed

Bark

• hidden by foliage
• smooth, gray-brown

Culture

• partial shade to full sun
• prefers moist, cool, acidic, well-drained, organic soil
• much more soil adaptable than most rhododendrons
• avoid harsh, dry, windswept sites

Landscape Use

• probably the most adaptable and easiest rhododendron to grow
• useful for dependable early spring bloom
• use in groups, mass plantings
• nice for winter foliage color
• shrub border
• woodland setting beneath high tree canopy
• exceptionally winter/cold hardy for a rhododendron

Liabilities

• getting to the point of overuse in places due to its adaptability and ease of growth
• some people find lavender-pink flower color objectionable
• phytophthora root rot
• desiccation in harsh situations
• rhododendron borer

ID Features

• dense, compact growth habit
• purple-plum winter foliage color
• heavy lavender-pink bloom in early spring
• leaves are smaller than R. carolinianum
• leaves are less pointed at apex than R. x laetevirens
• blooms before R. carolinianum

Propagation

• by late summer, fall, or winter cuttings
• also by tissue culture

Cultivars/Varieties

Rhododendron 'P.J.M.' is not a single cultivar, but rather a group of hybrids that were derived from a particular interspecific cross of R. carolinianum and R. dauricum var. sempervirens performed at Weston Nurseries in Massachusetts. Though the resulting seedlings have been relatively uniform, variability does exist in terms of plant habit, foliage color, flower color, bloom time and growth rate. A group of seedling offspring from a cross such as this is termed a grex. Below are listed some common 'P.J.M.' hybrid cultivars that are vegetatively propagated to assure uniformity. These plants are among the hardiest and most reliable evergreen rhododendrons.

'Elite' - This selection has bright pink-lavender flowers that bloom later than typical for 'P.J.M.'. It has a vigorous and somewhat upright growing habit.

'Northern Starburst'- A tetraploid form of 'P.J.M. Compact', this selection from a Washington State nursery offers larger flowers, thicker stems and thicker foliage. It is new and not widely tested in New England landscapes.

'P.J.M. Compact Form' - Not a true dwarf form, this tetraploid selection has larger blooms and larger, thicker foliage. It is an upright, bushy plant.

'P.J.M. Lavender' - This semi-dwarf selection flowers early with lavender-pink blooms. The green foliage becomes purple-brown in winter.

'P.J.M. Princess Susan' - A dwarf form that grows slowly, this plant bears lavender-purple flowers and darkly colored winter foliage.

'Regal' - This form has strong lavender-pink flowers that open before 'Elite' (mid-season for 'P.J.M.'). It does not get as tall as 'Elite', rather it grows vigorously with a more spreading habit.

'Victor' - An early-blooming selection of 'P.J.M.', it begins to flower before other types and grows slowly and more compactly.