When does mountain laurel bloom in Connecticut?

Most often in June. Across 142 dated, research-grade observations of Kalmia latifolia in Connecticut, the flowering season runs roughly June.

Peak June In flower 142 Examined 273 State Connecticut

Flowering 142 in flower of 273 examined

33%

91%

13%

10%

Proportion of examined Kalmia latifolia in Connecticut in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	8	0%	0% to 32%
Feb	0	1	too few examined
Mar	0	7	0%	0% to 35%
Apr	0	14	0%	0% to 22%
May	16	48	33%	22% to 47%
Jun	122	134	91%	85% to 95%
Jul	3	23	13%	5% to 32%
Aug	0	14	0%	0% to 22%
Sep	1	10	10%	2% to 40%
Oct	0	8	0%	0% to 32%
Nov	0	2	too few examined
Dec	0	4	too few examined

Peak flowering in Jun. Each bar is the share of Kalmia latifolia in Connecticut observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 142 of 273 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 3 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.wt38fd.

What this is, and what it is not

This is a record of when people in Connecticut found Kalmia latifolia in flower, not a forecast. It is computed only from observations made in Connecticut, so it is not the species’ global average dragged onto a map: the same plant flowers on different dates in different places, and that is the entire point of the page.

It will not tell you what your particular plant will do this year. Bloom time moves with the season, with altitude, and with the weather, and a warm February pulls everything forward. We publish the distribution and the sample size, and we refuse to draw a month that too few people examined.

The plant

Kalmia latifolia

mountain laurel

Sourcesevery claim on this page

GBIF (iNaturalist Research-grade Observations). Dated flowering annotations in Connecticut. Every record achieved iNaturalist quality grade Research, which is applied upstream at export. 10.15468/dl.wt38fd. Retrieved 2026-07-14.
World Flora Online Plant List. The accepted name. CC0. Retrieved 2026-07-12.