Carthamus (Safflower) in Zone 8a & 8b

Carthamus tinctorius

Yes, carthamus (safflower) grows in zones 8a and 8b. Start seeds indoors Feb 25–Mar 4 and plant out Mar 25–Apr 1.

When to plant carthamus (safflower) in zone 8b

Zones 8a and 8b share the same average frost dates, so this page covers both.

Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.

Start indoorsFeb 25–Mar 4
Direct sow / transplant outsideMar 25–Apr 1
Estimated bloomJun 23–Jun 30 (~90 days after planting)

Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1.5-2 ft.

Plant alongside it in zone 8b

These go outside within two weeks of carthamus (safflower) in zone 8b, so one planting day can cover them.

Carthamus (Safflower)
Photo: Jac. Janssen via Wikimedia Commons, CC BY 2.0, cropped.

Carthamus, better known as safflower, is a thistle-like cut flower historically grown as an oilseed and dye crop, with bright orange-yellow blooms that hold their color well once dried.

How carthamus (safflower) fits zone 8's season

Zone 8b's frost-free window runs about 230 days, from March 25 to November 10. Carthamus (safflower) needs about 90 days from sowing to first bloom.

Carthamus (Safflower) planting windows in every zone

Zone 8b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.

ZoneStart indoorsSow or plant outBloom
2a & 2bApr 22–Apr 29May 20–May 27Aug 18–Aug 25
3a & 3bMay 2–May 9May 30–Jun 6Aug 28–Sep 4
4a & 4bApr 17–Apr 24May 15–May 22Aug 13–Aug 20
5a & 5bApr 12–Apr 19May 10–May 17Aug 8–Aug 15
6a & 6bMar 28–Apr 4Apr 25–May 2Jul 24–Jul 31
7a & 7bMar 13–Mar 20Apr 10–Apr 17Jul 9–Jul 16
8a & 8b (your zone)Feb 25–Mar 4Mar 25–Apr 1Jun 23–Jun 30
9a & 9bJan 18–Jan 25Feb 15–Feb 22May 16–May 23
10a & 10bJan 2–Jan 9Jan 30–Feb 6Apr 30–May 7
11a & 11bDec 4–Dec 11Jan 1–Jan 8Apr 1–Apr 8

Bloom dates are about 90 days after the sow or plant-out date, not after starting seeds indoors.

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

No well-established companions for carthamus (safflower).

Where to buy carthamus seeds

None of the seed suppliers we list carries carthamus seeds right now. A local garden center or a specialty seed house is the place to look.

See why we recommend these suppliers →

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See it growing

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

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Growing Carthamus (Safflower) in USDA zone 8b

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Growing Carthamus (Safflower) in USDA zone 8b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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