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Whidbey Island

I grew several tall sunflowers right next to a few grown for head size. My question is whether cross pollination might be an issue causing the tall ones to be shorter and the big headed ones to be smaller or is the pollen right on the seed stamen the one that does the pollination?
Thanks.

10/22/2022 4:32:17 PM

Colorado

Yes they cross with whatever is open for the 4 or 5 days that the flower is open for business.Ive heard that they need pollen from another sunflower to produce viable seeds-they dont self like a tomato.

2/17/2023 12:02:37 AM

Partlow,Va

From my experience cojoe is correct. I let some self sib one year and the first year was okay. second year zero germination. the seeds looked fine. At first I thought I dried them to long....

2/17/2023 8:45:25 AM

Team Canuckle Heads

Agreed here as well.
Sunflowers prefer cross pollination.This is why I only grow tall varieties.

2/17/2023 6:14:55 PM

Tauranga, NZ

Hey John/all, when you say sunflowers prefer cross pollination what does that actually mean - have they genetically adapted in favour of cross-pollination, or is that more anecdotal based on your years of growing giant yellows. And if you don’t mind me asking what’s the significance of this process per your reference to tall varieties.

As I understand it, each disc floret opens a few at a time starting at the outer edge of the flower head, moving over time towards the centre. Since each floret is male first, then female after, there is always a window that the floret can self-pollinate from successive disc florets at the male stage.

Therefore I would presume that without removing the anther of each sunflower floret, a floret showing the stigma can be either cross-pollinated or self-pollinated, and that is a process of chance, depending on both the wind, and the foraging bee or local insect population.

Andrew

2/18/2023 9:11:10 AM

Team Canuckle Heads

This is the article I read on sunflower pollination.

Sunflowers are plants that can self-pollinate and cross-pollinate but sunflowers are more likely to cross-pollinate. Accordingly, if cross-pollination does not occur, a sunflower as a hermaphrodite plant can pollinate itself-even though this mechanism is inefficient with the rate of success at 2%.
https://scialert.net › fulltextmobile
Formation of Sunflower Seeds via Pollination Methodology ...

2/18/2023 8:42:15 PM

Team Canuckle Heads

I'm no expert, I just grow them for height not for big heads.

2/18/2023 8:45:00 PM