Hardiness Zone: 7a
Monica from Moab, UT
Herbicide drift or chemical residue in the soil is another common cause of multiple heads on sunflowers. Herbicides drifting over from other parts of the garden (or the neighbor's garden) can cause abnormal bending or twisting of stems and/or leaf petioles, slow growth, or cause the development of multiple heads. This happened to my neighbor this year. In her case, she didn't actually plant them, the birds and squirrels feeding at my bird feeders did. When sunflowers sprouted in her backyard she decided to leave them alone. As they grew, they developed multiple heads. The seeds carried to her yard from my feeders were black oil sunflower seeds. I imagine they were harvested from commercially grown sunflower crops that were grown in large fields. Even if these fields were not treated with herbicides, crops in nearby fields may have been. Meanwhile, a few weeks later and a mere 25 yards away, the mammoth sunflowers planted in my garden bloomed normally-none of them developed multiple heads. Could her multiple heads could have been herbicide drift? Maybe. Neither of us uses chemicals on our yards or gardens so it would have to have been the seeds. It remains a mystery.
Sunflowers are native to North America. In the wild they usually have multiple heads-up to 20 heads per flower is the norm. These wild seeds make up the genetic basis for the domesticated and hybrid seeds we see today. Could yours be cross-pollinating with nearby wild sunflowers? It's just another possibility.
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By Roxanne F.01/17/2014
I kinda have the opposite question: I'm growing the "sun king" variety of sunflower for ornamental purposes, and I would like to have several flowers on each plant, is that possible with some clever pruning? Thanks.
Read your message, I have the same problem. Mammoth Seed and all. Beautiful Tall, 12 Feet plants the first 2 years, then 6 footers with 10 or so flowers.
I would like an explaination too. I will add one thing. I added a mulch I picked up from the local landfill, supposed to be any way. My zucchini did not turn out at all, could not keep the plants alive.
If I can't grow zucchini I need help! The rest of the garden with the same "mulch" grew great tomatoes & green bell peppers. Still do want my sunnys back.
By darrellg in Oklahoma (Guest Post)07/28/2006
Try planting in a different spot each year . If you are still planting in the same spot each time you are using up the vitamins and minerals that they feed from. Just try rotating crops, plant something different there next year & your sunflowers else where. It also goes for any plant to rotate.
By (Guest Post)07/28/2006
I would say if you are fertilizing you may be using too much or maybe you have a hybrid seed?
Go check out this website and ask you question there, they are great for all gardening needs!
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