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When to plant ornamental alliums

Plant ornamental alliums for fall from 6 weeks before to 2 weeks after the first fall frost.

Your dates for ornamental alliums

Set your ZIP code at the top of the page and we will work out when to plant ornamental alliums where you live, from the frost records of the nearest NOAA weather station. Your ZIP code is remembered on this device only.

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Ornamental Alliums planting dates by zone

JFMAMJJASOND Zone 4b Zone 5b Zone 6b Zone 7b Zone 8b Zone 9a
Fall plantingDates use each zone's typical frost dates. Enter your ZIP code for your own.
Dates from each zone's typical (median) frost dates.
ZoneFall planting
Zone 2a *Jul 25 to Sep 19
Zone 3a *Aug 3 to Sep 28
Zone 3b *Aug 13 to Oct 8
Zone 4aAug 17 to Oct 12
Zone 4bAug 20 to Oct 15
Zone 5aAug 23 to Oct 18
Zone 5bAug 29 to Oct 24
Zone 6aSep 5 to Oct 31
Zone 6bSep 10 to Nov 5
Zone 7aSep 13 to Nov 8
Zone 7bSep 20 to Nov 15
Zone 8aSep 26 to Nov 21
Zone 8bOct 2 to Nov 27
Zone 9a *Oct 15 to Dec 10
Zone 9b *Oct 28 to Dec 23

* Outside zones 4 to 8, the hardiness range our sources give for ornamental alliums. Plants there may not survive the winter or get enough winter chill, and are usually grown as annuals or in pots.

Where frost is rare

Clemson lists Naples onion (A. neapolitanum), drumstick allium (A. sphaerocephalon), A. oreophilum (sold as A. ostrowskianum) and star of Persia (A. christophii) as alliums that do well in South Carolina. Austin-area extension lists the Texas native A. drummondii and rosy garlic (A. roseum), both of which reseed aggressively. Avoid overly wet sites, which lead to bulb rot. No warm-climate source gives planting months or a pre-chilling requirement.

How to grow ornamental alliumsYour full planting calendar

Sources