When does Black Medick bloom in New York?

Most often in September. Across 344 dated, research-grade observations of Medicago lupulina in New York, the flowering season runs roughly April to October.

Peak September In flower 344 Examined 382 State New York

Flowering 344 in flower of 382 examined

94%

93%

94%

84%

88%

94%

83%

71%

Proportion of examined Medicago lupulina in New York in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	0	too few examined
Feb	0	2	too few examined
Mar	0	1	too few examined
Apr	15	16	94%	72% to 99%
May	108	116	93%	87% to 96%
Jun	134	143	94%	88% to 97%
Jul	26	31	84%	67% to 93%
Aug	21	24	88%	69% to 96%
Sep	16	17	94%	73% to 99%
Oct	10	12	83%	55% to 95%
Nov	12	17	71%	47% to 87%
Dec	2	3	too few examined

Peak flowering in Sep. Each bar is the share of Medicago lupulina in New York 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. 344 of 382 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 4 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 New York found Medicago lupulina in flower, not a forecast. It is computed only from observations made in New York, 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

Medicago lupulina

Black Medick

Sourcesevery claim on this page

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