# Milkweed in Washington

> 3 milkweed species are recorded in Washington.

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

## Overview

Nearly all of Washington’s milkweed is east of the Cascades, where showy milkweed lines irrigation ditches and the Columbia Basin’s shrub-steppe supports narrowleaf milkweed. Western Washington has very little native milkweed and correspondingly few breeding monarchs.

- Species recorded: 3
- USDA hardiness zones: 4a–9a
- Monarch flyway: western
- Best time to sow seed outdoors: October to December, so the seed uses winter rain

## Species recorded in Washington

| Common name | Scientific name | Native | Height | Bloom |
| --- | --- | --- | --- | --- |
| Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August |
| Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September |
| Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June |

## How to cite

Milkweed USA. (2026). Milkweed in Washington. https://milkweedusa.com/states/washington/