# Milkweed in Montana

> 8 milkweed species are recorded in Montana.

Source: https://milkweedusa.com/states/montana/  
Licence: CC BY 4.0 (Milkweed USA)

## Overview

Montana sits on the divide between eastern and western monarch populations, with showy milkweed along the Yellowstone and Missouri river systems and green comet milkweed on dry prairie. Riparian corridors matter enormously here, being the only reliably moist habitat for hundreds of miles.

- Species recorded: 8
- USDA hardiness zones: 3a–6a
- Monarch flyway: both
- Best time to sow seed outdoors: September to November, before the ground freezes

## Species recorded in Montana

| Common name | Scientific name | Native | Height | Bloom |
| --- | --- | --- | --- | --- |
| Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September |
| Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August |
| Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August |
| Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September |
| Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July |
| Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August |
| Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September |
| Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August |

## How to cite

Milkweed USA. (2026). Milkweed in Montana. https://milkweedusa.com/states/montana/