When does Madagascar Periwinkle bloom in Florida?

Most often in January. Across 530 dated, research-grade observations of Catharanthus roseus in Florida, the flowering season runs roughly January to December.

Peak January In flower 530 Examined 543 State Florida

Flowering 530 in flower of 543 examined

Proportion of examined Catharanthus roseus in Florida in flower, by month
Month In flower Examined Share 95% interval
Jan 66 66 100% 95% to 100%
Feb 20 23 87% 68% to 95%
Mar 51 51 100% 93% to 100%
Apr 42 42 100% 92% to 100%
May 33 35 94% 81% to 98%
Jun 26 26 100% 87% to 100%
Jul 28 28 100% 88% to 100%
Aug 36 39 92% 80% to 97%
Sep 42 45 93% 82% to 98%
Oct 64 65 98% 92% to 100%
Nov 69 70 99% 92% to 100%
Dec 53 53 100% 93% to 100%

Peak flowering in Jan. Each bar is the share of Catharanthus roseus in Florida 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. 530 of 543 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 Florida found Catharanthus roseus in flower, not a forecast. It is computed only from observations made in Florida, 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

Sourcesevery claim on this page

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