Both Ericaceae

Kalmia latifolia vs Rhododendron maximum

These two are not on this page because a keyword tool suggested them. They are here because our own identification model genuinely mistook one for the other, on real photographs, 3 times. We publish the rate, and then we tell you what actually separates them.

Confused 3x by our model Method published

Side by sidefigs. a and b

Kalmia latifolia, photographed by Sean Haight
fig. a Sean Haight, CC0 1.0

Kalmia latifolia

mountain laurel
Rhododendron maximum, photographed by Lynn Harper
fig. b Lynn Harper, CC0 1.0

Rhododendron maximum

great rhododendron

How often our model gets it wrong measured, not estimated

When the plant was The model said How often
Rhododendron maximum Kalmia latifolia 3 of 20 (15%)

Measured on 38,299 openly licensed, research-grade photographs. Full method and dataset.

What actually separates themon the record

Family Both Ericaceae. The family does not separate them.
Genus Kalmia versus Rhododendron.
Flowering Peaks in June versus July. If the plant is in flower, timing helps. (n = 6,220 and 1,372.)

What we do not have yet: the diagnostic morphological character that a botanist would key on, from a source we can cite. We are not going to invent one. Until we have it, this page tells you the two are genuinely confusable, how often, and what the taxonomy and the flowering data do and do not settle.

Both recordsfull pages