Eric- the pics I've seen of them, they've come up larger than marigolds but will be smaller than the big sunflowers. I have a slightly similar experience. I sew BOSS 3 mths ago, transplanted them in 4 different locations and not one bloomed. Instead, they grew to a certain height, then curled up and died....

Aww how sad! I tried last year, but the rabbits gobbled them up just after I transplanted them. This is very odd! I was hoping to have large sunflowers to shade my hostas from the full sun.

black oil sunflowers have been cross pollinated and cross bred to produce more oil or be drought resistant or make bigger heads ect. but like many engineered seeds they sometimes revert back to a native plant. they are often hybrids and don't produce true.it's just like planting apple seeds they often have a root base of crabapple stock to be more hardy but revert back to crabapples! your best bet to get best seed is get some from a farm supply or grain elevater that are bred right for seed

There are also certain plants that don't do well being transplanted. Try sowing directly, and I think you'll like the results. There are dozens of varieties in all shapes, sizes, and colors. We had one once that reached 18 feet tall with over 100 heads. That or you can get those with one very large head (Mammoth). Regardless, they all make beautiful heads, and the birds just love them. They are also notorious for reseeding. I still have them popping up in my blueberry patch after several years' absence. You can find them from most seed companies. Baker Creek, I think, has a decent selection.

Thanks all! Some were transplanted and some were directly sowed. All the same results :( I will try some Burpee sunflower seeds next year. I guess gardening is trial and error. I will plant the mini ones next year too. They are so adorable and look great among the wildflowers!

when you get some more seed to plant the black oil seed is black shell and bred up to produce more oils and its what is best for small birds. the striped sunflower seeds are larger and tougher shell and are bred up to produce bigger seeds for eating and cooking ect. and the shells are thicker and tougher and some of the little birds can't crack them. so I plant or put out both kinds but go heavy to the black oil seeds.

Thanks for the tip dklucius! I will plant a whole varietyof sunflowers for the birds! I really like the red ones I saw online.

I would assume that the reason for small plants and flowerheads is due to limited root growth in a shallow soil environment. You essentially created a bonsai sunflower. Sunflowers generally do best in the ground where they can develope a large root system.

Mike

Hmm I don't think I have shallow garden soil. It Itis a raised bed tilled deep and spread with a layer of garden soil. The other plants in it aren't bonsaied though. Hmm very strange. The sunflower is looking a little bigger lately. A bit bigger than a marigold, but smaller than a cosmo.

Maybe they are sprayed with something to keep them from sprouting .I know some veggies like potatoes are. Just a thought

I'm sorry Eric. I had thought that you had grown the sunflowers in an old birdbath. So you had transplanted the seedlings to a garden bed?
I have grown some of the smaller Sunflowers (colourful Italian hybrids) in the past because they tend to give many more blooms than the larger types and are better for use as cut flowrers. The plants still usually reach about three feet tall with flowers from 4"-6" across.

I wonder if the root system was damaged after transplanting and it just took a while for the plant to establish again. I have always found that Sunflowers are very hard to transplant.

Mike

I don't think the root was damaged. When I found the plant in the birdbath, it had just sprouted with a tiny root coming out of the seed. The rest of the sunflowers where planted in the garden. I think I'm going to get a picture of a huge bee on the tiny sunflower :) Thanks for all the tips guys!