When does multiflora rose bloom in Connecticut?

Most often in June. Across 119 dated, research-grade observations of Rosa multiflora in Connecticut, the flowering season runs roughly June.

Peak June In flower 119 Examined 255 State Connecticut

Flowering 119 in flower of 255 examined

Proportion of examined Rosa multiflora in Connecticut in flower, by month
Month In flower Examined Share 95% interval
Jan 0 6 0% 0% to 39%
Feb 0 1 too few examined
Mar 0 5 0% 0% to 43%
Apr 0 11 0% 0% to 26%
May 20 40 50% 35% to 65%
Jun 99 110 90% 83% to 94%
Jul 0 14 0% 0% to 22%
Aug 0 18 0% 0% to 18%
Sep 0 7 0% 0% to 35%
Oct 0 27 0% 0% to 12%
Nov 0 8 0% 0% to 32%
Dec 0 8 0% 0% to 32%

Peak flowering in Jun. Each bar is the share of Rosa multiflora in Connecticut 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. 119 of 255 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 Connecticut found Rosa multiflora in flower, not a forecast. It is computed only from observations made in Connecticut, 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 Connecticut. 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.