Rhododendron 'PJM'
Rhododendron 'PJM' · Ericaceae Popular
Vivid lavender-pink flowers cover this tough evergreen in early spring, and the leaves turn deep burgundy for winter. It needs acidic soil and shelter from drying wind.
- Size
- 5 ft tall, 5 ft wide
- Zones
- 4 to 8
- Light
- Part sun to part shade
- Flowers
- Late April to mid May
- Pets
- Toxic (severe)
- Job in a bed
- Anchor
A bed built around rhododendron 'PJM'
The planner designed this bed around rhododendron 'PJM' when this page was made: a 16 × 8 ft (4.9 × 2.4 m) English border in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why rhododendron 'PJM' stands where it does.
The plants
- 1 Rhododendron 'PJM' × 1, purple
- 2 Striped bloody cranesbill × 16, pink
- 3 Carpathian bellflower × 9, blue
- 4 Joe Pye weed 'Little Joe' × 4, pink
- 5 Foxglove beardtongue × 5, white
- 6 Coneflower 'PowWow Wild Berry' × 5, pink
- 7 Asiatic lily × 4, yellow
- 8 Easter lily × 5, white
- 9 Daffodil × 3, orange
Why this plant
- The bed's only structure. Shrubs and grasses keep their shape when the perennials die down, and it is the only one here.
- The only dense clusters. The others are open bowls, bells, flat plates and others. Shape reads at a distance, where colours blur.
- The only purple.
Why here
- Anchors a back corner. At 5 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to Joe Pye weed 'Little Joe' (4 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A shrub is seen as an object, and needs clear ground around it.
Why now
- In flower for four weeks. From late April to mid May.
- Fills a gap. For one of those weeks nothing else on the plan is in flower.
- The only leaves in winter. From November to March it is what there is to look at.
Planned as an English border: 6 of the 7 groups (86%) are drifts, longer along the bed than they are deep. The bed is balanced: the left half carries 52% of the visual weight and the right half 48%. Striped bloody cranesbill is planted in four places along the bed, which gives it rhythm.
The planner's own design check: 11 Excellent, 6 Good.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where rhododendron 'PJM' goes in a border
At 5 ft it belongs at the back of a bed. In the planner's ten height classes it is tall (4 to 5 ft).
Its job: anchor. A shrub that gives the bed permanent structure. Planted singly, as soon as the front edge is laid; everything else is arranged around it.
Evergreen, so it holds the bed together in winter, and its flowers come before the trees leaf out. It must have acid soil; in lime it yellows and dies. Underplant it with shade perennials that like the same conditions.
- Early spring colour in part shade
- Evergreen structure for a woodland bed
- Acid soil
What to plant with rhododendron 'PJM'
Plants recorded as good partners for it, and what each pairing does:
- Hosta: its green leaves are a setting for the flowers, before and after; bold leaves against its medium ones; spires rising out of its mound.
- Japanese painted fern: its silver leaves are a setting for the flowers, before and after; low enough (18 in) to stand in front of it; happy in the same moist soil.
- Lenten rose: in flower together for three weeks, from late April; bold leaves against its medium ones; low enough (18 in) to stand in front of it.
Choosing between it and a look-alike? Rhododendron 'PJM' vs Evergreen azalea.
Questions about rhododendron 'PJM'
Does rhododendron 'PJM' need sun or shade?
Rhododendron 'PJM' grows in part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).
It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells.
What zones does rhododendron 'PJM' grow in?
USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does rhododendron 'PJM' flower in my zone?
In zone 5 it flowers late April to mid May. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 4 | Early May to late May |
|---|---|
| Zone 5 | Late April to mid May |
| Zone 6 | Mid April to early May |
| Zone 7 | Mid April to early May |
| Zone 8 | Early April to late April |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should rhododendron 'PJM' be planted?
4 ft (120 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 5 ft (150 cm), so a group knits into one patch.
It grows 5 ft (150 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many rhododendron 'PJM' plants do I need?
Usually one. At 4 ft (120 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 4 ft apart: three plants for a 10 ft run.
In the bed above, the planner used one in one group.
Is rhododendron 'PJM' poisonous to dogs and cats?
Yes: severe toxicity to people, dogs, cats and horses. All parts, including the nectar, are highly poisonous if eaten and can affect the heart. Even a few leaves can make a pet seriously ill.
Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like rhododendron 'PJM'?
These come closest to doing what rhododendron 'PJM' does, and no toxicity is recorded for them:
- Fothergilla 'Mount Airy': the same job in a bed, the same size and the same flowering time; white, not purple, not evergreen.
- Camellia 'April Blush': the same job in a bed and the same size; flowers late March to early May, pink, not purple.
- Koreanspice viburnum: the same job in a bed, the same size and the same flowering time; white, not purple, not evergreen.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
What flowers after rhododendron 'PJM'?
Rhododendron 'PJM' is over by mid May. These start as it finishes and carry the same spot on, so it never goes flat:
- Blue false indigo: from late May to mid June, 4 ft tall.
- Foxglove: from early June to mid July, 4 ft tall.
- Lupine: from late May to early July, 3½ ft tall, to stand in front of it and cover its fading stems.
What does rhododendron 'PJM' look like in winter?
Rhododendron 'PJM' keeps its dark green and burgundy leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
More Rhododendron
- Azalea 'Delaware Valley White' Rhododendron 'Delaware Valley White'
- Azalea 'Hino-Crimson' Rhododendron 'Hino-Crimson'
- Catawba rhododendron Rhododendron catawbiense
- Evergreen azalea Rhododendron (Kurume hybrids)
- Flame azalea Rhododendron calendulaceum
- Korean rhododendron 'Cornell Pink' Rhododendron mucronulatum 'Cornell Pink'
- Northern Lights azalea Rhododendron (Northern Lights Group)
- Pinxterbloom azalea Rhododendron periclymenoides
- Reblooming azalea Rhododendron (Encore Group)
- Rhododendron 'Cunningham's White' Rhododendron 'Cunningham's White'
- Rhododendron 'Nova Zembla' Rhododendron 'Nova Zembla'
- Rhododendron 'Olga Mezitt' Rhododendron 'Olga Mezitt'
- Rhododendron 'Purple Gem' Rhododendron 'Purple Gem'
- Rhododendron 'Roseum Elegans' Rhododendron 'Roseum Elegans'
- Rosebay rhododendron Rhododendron maximum
- Royal azalea Rhododendron schlippenbachii
- Swamp azalea Rhododendron viscosum
- Yak rhododendron Rhododendron yakushimanum
In these guides
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Evergreen shrubs for structure
- Plants with purple and burgundy leaves
Every fact on record
- Type
- Shrub
- Size
- 5 ft (150 cm) tall, 5 ft (150 cm) wide
- Plant
- 4 ft (120 cm) apart
- Height class
- Tall (4 to 5 ft)
- Place in the bed
- Back
- Flowers
- Late April to mid May; dense clusters; purple
- Leaves
- Medium texture, evergreen; dark green, burgundy
- Shape
- Rounded, clumping
- Hardy in
- USDA zones 4 to 8
- Light
- Part sun, part shade
- Soil
- Rich, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Ericaceae
Checked against NC State Extension and ASPCA poison lists. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.