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Cut flowers5 varieties

Sunflower

Helianthus annuus

Fast-growing warm-season annual with upright stems and showy flower heads in many colors and forms.

annualFull sunHardy to 25°FFrost TenderDirect-Sow
Sunflower in the field

Days to maturity

50–110 days

Days to germ.

7–14 days

Spacing

4–24 in

Height

36–180 in

Sun

Sun

Vase life

5–7 days

How we grow it

Germination

Days to germ.
7–14 d
Soil temp
70–75 °F
Depth
0.5 in
Pre-treatment
None, but can soak seeds for up to 3 hours before sowing to speed germination.
Viability
3 yrs

Culture

Days to maturity
50–110 d
Spacing
4–24 in
Height
36–180 in
Sun
Sun
Frost
Hardy to ~32°F · to 32°F · tender
Sow indoors
No
Outdoor / direct
Yes

Harvest

Cut stage
When petals have color and just begin to lift away from center disc, but before the bloom is fully open.
Vase life
5–7 d
Handling
Store out of direct sunlight; re-cut stems every 2 days
Notes
Yield: One stem per plant. SeeDS: When petals wither and drop, back of heads turn yellow-brown, and seeds get plump, cut with 1-2 ft of stem and hang by stem to dry. After 1-2 d, rub flower face to remove dried seeds.

Recent field notes

Observation

First blossoms

Observation

I’d estimate the tallest of these is just over 12” tall.

Observation

First seedlings spotted.

Varieties

5 varieties on record