When does koaoha bloom in Hawaii?

Most often in January. Across 87 dated, research-grade observations of Acacia heterophylla in Hawaii, the flowering season runs roughly January to March.

Peak January In flower 87 Examined 171 State Hawaii

Flowering 87 in flower of 171 examined

79%

78%

75%

57%

50%

20%

33%

22%

33%

20%

13%

62%

Proportion of examined Acacia heterophylla in Hawaii in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	19	24	79%	60% to 91%
Feb	14	18	78%	55% to 91%
Mar	12	16	75%	51% to 90%
Apr	8	14	57%	33% to 79%
May	10	20	50%	30% to 70%
Jun	3	15	20%	7% to 45%
Jul	6	18	33%	16% to 56%
Aug	2	9	22%	6% to 55%
Sep	2	6	33%	10% to 70%
Oct	2	10	20%	6% to 51%
Nov	1	8	13%	2% to 47%
Dec	8	13	62%	36% to 82%

Peak flowering in Jan. Each bar is the share of Acacia heterophylla in Hawaii 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. 87 of 171 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 Hawaii found Acacia heterophylla in flower, not a forecast. It is computed only from observations made in Hawaii, 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

Acacia heterophylla

koaoha

Sourcesevery claim on this page

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