When to Plant Alliums in Oregon

Ornamental alliums (Allium spp.) bridge the gap between spring and summer with their striking globe-shaped flower heads in shades of purple, violet, white, and pink. Blooming after tulips have faded, they extend the spring display well into early summer. 'Gladiator', 'Globemaster', and 'Purple Sensation' produce softball-sized heads on 18–36 inch stems, while smaller species create charming accents at border fronts. Deer and rodents shun them completely due to the characteristic onion scent. Dried seed heads provide architectural interest into fall.

Oregon spans USDA hardiness zones 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

Find Your County

Click your county for exact Alliums planting dates based on your local frost dates.

Hover over a county to see details. Click to view planting guide.

Alliums Planting Calendar for Oregon

▸ Zone 6a ~193 day growing season · Full guide →

Last frost: April 10 · First frost: October 20 · 193 day season

Activity	When	Date Range
Bloom	October 6	Oct 6 – Nov 3
Fall Sowing	September 8	Sep 8 – Sep 22

▸ Zone 6b ~205 day growing season · Full guide →

Last frost: April 3 · First frost: October 25 · 205 day season

Activity	When	Date Range
Bloom	October 11	Oct 11 – Nov 8
Fall Sowing	September 13	Sep 13 – Sep 27

▸ Zone 7a ~221 day growing season · Full guide →

Last frost: March 25 · First frost: November 1 · 221 day season

Activity	When	Date Range
Bloom	October 25	Oct 25 – Nov 15
Fall Sowing	September 27	Sep 27 – Oct 11

▸ Zone 7b ~235 day growing season · Full guide →

Last frost: March 18 · First frost: November 8 · 235 day season

Activity	When	Date Range
Bloom	November 1	Nov 1 – Nov 22
Fall Sowing	October 4	Oct 4 – Oct 18

▸ Zone 8a ~255 day growing season · Full guide →

Last frost: March 8 · First frost: November 18 · 255 day season

Activity	When	Date Range
Bloom	November 11	Nov 11 – Dec 2
Fall Sowing	October 14	Oct 14 – Oct 28

▸ Zone 8b ~276 day growing season · Full guide →

Last frost: February 25 · First frost: November 28 · 276 day season

Activity	When	Date Range
Bloom	November 28	Nov 28 – Dec 19
Fall Sowing	October 31	Oct 31 – Nov 14

▸ Zone 9a ~303 day growing season · Full guide →

Last frost: February 10 · First frost: December 10 · 303 day season

Activity	When	Date Range
Bloom	December 10	Dec 10 – Dec 31
Fall Sowing	November 12	Nov 12 – Nov 26

▸ Zone 9b ~329 day growing season · Full guide →

Last frost: January 25 · First frost: December 20 · 329 day season

Activity	When	Date Range
Bloom	December 27	Dec 27 – Jan 17
Fall Sowing	November 29	Nov 29 – Dec 13

Growing Tips for Oregon

Plant bulbs in fall, 3–4 times as deep as the bulb diameter (typically 4–6 inches for large types, 3 inches for small species). Space 6–8 inches apart for standard cultivars. Foliage often looks untidy as it dies back before bloom — plant around perennials that will conceal the yellowing leaves. Excellent drainage is essential; alliums rot in wet soils. Leave bulbs in place for naturalization; divide every 3–4 years when clusters become congested. Deadhead spent globes or leave for ornamental seedheads and self-sowing.

Alliums in Other States

Frequently Asked Questions

When should I plant Alliums in Oregon?

Planting dates for Alliums in Oregon depend on your USDA zone. Oregon spans zones 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Oregon for planting?

Oregon contains USDA hardiness zones 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Blog