Rosebay rhododendron

Questions about rosebay rhododendron

Does rosebay rhododendron need sun or shade?

Rosebay rhododendron grows in part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).

It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells.

What zones does rosebay rhododendron grow in?

USDA zones 3 to 7. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).

Above zone 7 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 rosebay rhododendron flower in my zone?

In zone 5 it flowers late June to mid July. As a summer flower it moves about half a week for every zone: earlier where it is warmer.

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 rosebay rhododendron be planted?

11½ ft (350 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 13 ft (400 cm), so a group knits into one patch.

It grows 15 ft (450 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many rosebay rhododendron plants do I need?

Usually one. At 11½ ft (350 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 11½ ft apart: one plant for a 10 ft run.

In the bed above, the planner used one in one group.

Is rosebay rhododendron 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.

Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.

Is there a pet-safe plant like rosebay rhododendron?

These come closest to doing what rosebay rhododendron does, and no toxicity is recorded for them:

• White fringe tree: the same job in a bed and the same colour; 20 in wider, flowers late May to early June.
• Shadblow serviceberry: the same job in a bed and the same colour; 20 in narrower, flowers mid April to early May.
• Japanese maple 'Bloodgood': the same job in a bed; 20 in wider, grown for its leaves, not its flowers.

Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.

Do deer eat rosebay rhododendron?

They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.

What flowers after rosebay rhododendron?

Rosebay rhododendron is over by mid July. These start as it finishes and carry the same spot on, so it never goes flat:

• Lilyturf: from early August to mid September, 16 in tall, to stand in front of it and cover its fading stems.
• Summersweet: from mid July to mid August, 6½ ft tall, to stand in front of it and cover its fading stems.
• Hosta 'Guacamole': from early August to late August, 24 in tall, to stand in front of it and cover its fading stems.

What does rosebay rhododendron look like in winter?

Rosebay rhododendron keeps its dark green leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.

Is rosebay rhododendron good for bees and butterflies?

Rosebay rhododendron is visited by pollinators, bees, specialist bees, butterflies and hummingbirds.

It is native to the United States and Canada.