# Milkweed in Iowa

> 16 milkweed species are recorded in Iowa.

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

## Overview

Iowa produces a disproportionate share of the eastern monarch population, almost entirely from roadside plantings, CRP acres and cemetery prairies in a landscape that is otherwise more than 85 percent cultivated. The state’s integrated roadside vegetation management program is a national model.

- Species recorded: 16
- USDA hardiness zones: 4b–6a
- Monarch flyway: eastern
- Best time to sow seed outdoors: late October to early December

## Species recorded in Iowa

| Common name | Scientific name | Native | Height | Bloom |
| --- | --- | --- | --- | --- |
| Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September |
| Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September |
| Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August |
| Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July |
| Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July |
| Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July |
| 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 |
| Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July |
| Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June |
| 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 |
| Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August |
| Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August |
| Mead’s Milkweed | Asclepias meadii | Yes | 1 ft–2 ft | May to June |
| Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June |

## How to cite

Milkweed USA. (2026). Milkweed in Iowa. https://milkweedusa.com/states/iowa/