When does East Maui Silversword bloom in Hawaii?

Most often in August. Across 55 dated, research-grade observations of Argyroxiphium sandwicense in Hawaii, the flowering season runs roughly August.

Peak August In flower 55 Examined 130 State Hawaii

Flowering 55 in flower of 130 examined

33%

13%

47%

79%

100%

43%

40%

36%

11%

Proportion of examined Argyroxiphium sandwicense in Hawaii in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	9	0%	0% to 30%
Feb	2	6	33%	10% to 70%
Mar	1	8	13%	2% to 47%
Apr	1	12	8%	1% to 35%
May	1	2	too few examined
Jun	7	15	47%	25% to 70%
Jul	19	24	79%	60% to 91%
Aug	13	13	100%	77% to 100%
Sep	3	7	43%	16% to 75%
Oct	2	5	40%	12% to 77%
Nov	4	11	36%	15% to 65%
Dec	2	18	11%	3% to 33%

Peak flowering in Aug. Each bar is the share of Argyroxiphium sandwicense 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. 55 of 130 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. 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 Argyroxiphium sandwicense 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

Argyroxiphium sandwicense

East Maui Silversword

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.