great laurel
Rhododendron maximum · Ericaceae
great laurel (Rhododendron maximum) is a perennial tree in the Ericaceae family. It is native to North America. USDA records it as hardy in zone 5 and warmer, down to about -13°F.
⚠ Allelopathic. USDA flags this plant as releasing compounds that can suppress the growth of plants near it. Give neighbours extra room, and expect some companions to struggle regardless of how well their conditions match.
Both flags are quoted from USDA PLANTS, not inferred.
At a glance
| Type | tree Derived |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 25 ft USDA |
| Light | shade USDA |
| Water need | medium USDA |
| Growth rate | slow USDA |
| Soil pH | 4–5.5 USDA |
| Bloom | April–May USDA |
| Flower color | Red USDA |
| Hardiness zones | 5 and warmer USDA |
| Guild layer | understory Derived |
| Nursery availability | Routinely Available USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It tolerates full shade. USDA rates it as having moderate water needs. Its drought tolerance is rated high. It is recorded on soils from pH 4 to 5.5 — acidic ground. Its cold limit is zone 5.
Size and growth
At maturity it reaches about 25 ft, making it a substantial woody plant. It grows slowly.
Bloom period
USDA records a bloom period of April through May. Flowers are red.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is dark green, coarse in texture. Its flowers are conspicuous. It carries conspicuous autumn colour. Its active growth period is spring and summer. Its winter foliage is dense, which makes it useful for year-round screening. USDA rates its lifespan as long.
What the site needs to provide
USDA records it across sites receiving 36 to 60 inches of annual precipitation. It needs at least 150 frost-free days to finish its season. It roots to at least 18 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.
Propagating it
It takes readily from seed, cuttings, bare root and container stock. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It does not spread vegetatively, so it will stay where you put it.
Resilience and wildlife
Its fire tolerance is rated medium, and it can resprout after damage. Its growth form is recorded as multiple stem.
Role in a guild
Understory. In a layered planting this is the layer beneath the canopy, tall enough to hold structure but shaded from above. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Others in Rhododendron
- Cascade azalea Rhododendron albiflorum
- smooth azalea Rhododendron arborescens
- dwarf azalea Rhododendron atlanticum
- rhodora Rhododendron canadense
Similar role and hardiness
- halberdleaf rosemallow Hibiscus laevis
- crimsoneyed rosemallow Hibiscus moscheutos
- sourwood Oxydendrum arboreum
- pomegranate Punica granatum
- blackjack oak Quercus marilandica
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol RHMA4, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Allelopathy, Bloom, Bloom end, cold stratification, Drought tolerance, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer, Type.
Read our full data sources and methodology.
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