Sunflower in Zone 2a & 2b

Helianthus annuus

Yes, sunflower grows in zones 2a and 2b. Plant it outside May 20–May 27.

When to plant sunflower in zone 2b

Zones 2a and 2b share the same average frost dates, so this page covers both.

Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.

Start indoorsNot typically started indoors
Direct sow / transplant outsideMay 20–May 27
Estimated bloomAug 8–Aug 15 (~80 days after direct-sowing)

Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 3-12 ft.

Plant alongside it in zone 2b

These go outside within two weeks of sunflower in zone 2b, so one planting day can cover them.

Sunflower
Photo: Yusumchen via Wikimedia Commons, CC BY-SA 4.0, cropped.

Sunflowers are one of the few flowers in a vegetable garden that does actual structural work: a single or branching stalk anywhere from 3 to 12-plus feet tall, topped with big daisy-form heads (yellow petals ringing a dark brown center, though some varieties run red or bronze), can serve as a living trellis for pole beans or climbing cucumbers, instead of building one out of stakes and twine.

How sunflower fits zone 2's season

Zone 2b's frost-free window runs about 104 days, from May 20 to September 1. Sunflower needs about 80 days from sowing to first bloom.

Sunflower planting windows in every zone

Zone 2b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.

ZoneStart indoorsSow or plant outBloom
2a & 2b (your zone)Not usuallyMay 20–May 27Aug 8–Aug 15
3a & 3bNot usuallyMay 30–Jun 6Aug 18–Aug 25
4a & 4bNot usuallyMay 15–May 22Aug 3–Aug 10
5a & 5bNot usuallyMay 10–May 17Jul 29–Aug 5
6a & 6bNot usuallyApr 25–May 2Jul 14–Jul 21
7a & 7bNot usuallyApr 10–Apr 17Jun 29–Jul 6
8a & 8bNot usuallyMar 25–Apr 1Jun 13–Jun 20
9a & 9bNot usuallyFeb 15–Feb 22May 6–May 13
10a & 10bSpring windowNot usuallyFeb–Aug~80 days after direct-sowing
11a & 11bNot usuallyJan 1–Jan 8Mar 22–Mar 29

Bloom dates are about 80 days after the sow or plant-out date.

Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.

Good companions

Where to buy sunflower seeds

Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's sunflower seeds)

Varieties we recommend, and where to get them:

See why we recommend these suppliers →

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See it growing

Search YouTube for "growing sunflower" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)

← Back to the full zone 2b calendar · Plan your beds in the Garden Designer →

Growing Sunflower in USDA zone 2b

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Growing Sunflower in USDA zone 2b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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