When does sourwood bloom in North Carolina?

Most often in July. Across 148 dated, research-grade observations of Oxydendrum arboreum in North Carolina, the flowering season runs roughly July.

Peak July In flower 148 Examined 616 State North Carolina

Flowering 148 in flower of 616 examined

48%

62%

26%

Proportion of examined Oxydendrum arboreum in North Carolina in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	15	0%	0% to 20%
Feb	0	13	0%	0% to 23%
Mar	0	7	0%	0% to 35%
Apr	0	59	0%	0% to 6%
May	0	61	0%	0% to 6%
Jun	81	170	48%	40% to 55%
Jul	54	87	62%	52% to 72%
Aug	10	39	26%	15% to 41%
Sep	2	56	4%	1% to 12%
Oct	1	71	1%	0% to 8%
Nov	0	25	0%	0% to 13%
Dec	0	13	0%	0% to 23%

Peak flowering in Jul. Each bar is the share of Oxydendrum arboreum in North Carolina 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. 148 of 616 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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 North Carolina found Oxydendrum arboreum in flower, not a forecast. It is computed only from observations made in North Carolina, 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

Oxydendrum arboreum

sourwood

Sourcesevery claim on this page

GBIF (iNaturalist Research-grade Observations). Dated flowering annotations in North Carolina. 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.