More than you ever wanted to know about sunflowers

I think Beo shares my interest in the versatility of sunflowers. They are attractive and easy to grow, they have edible seeds, they can be used to make oil, the leaves make decent livestock feed, and in some types (like sunchokes), the root system forms edible, starchy tubers that taste something like water chestnuts or potatoes.

I developed a particular interest when I found out that sunflower seed hulls can be used as fuel for my biomass stove. I had this wacky idea to find or develop perennial sunflowers that produced seeds comparable to the big annuals we're all familiar with. Then we could eat the seeds (or make oil from them), burn the hulls for winter heat, and feed the rest to the goats. And perennial means I don't have to replant every year!

So excuse me while I nerd out on sunflowers for a few thousand words...

I did some googling on crossing sunflower species. I ran across a forum posting from a man by the name of Walter Pickett. It turns out Mr. Pickett used to work on hybridizing perennial sunflowers for a living, at the venerable Land Institute. On a whim, I emailed him. I told him I was interested in finding out about perennial sunflowers with high seed yeilds. He was kind enough to write an extensive reply to my very brief query. Here is what I learned:

The Maximillian sunflower (Helianthus maximillianii) is a commonly available perennial sunflower. It produces 900 lbs of small seeds per acre, as well as edible rhizomes (similar to sunchokes, though lower yield).

By crossing H. maximillianii with another perennial sunflower, H. salicifolius, the yield dropped to 300 lbs per acre, but the seeds were much larger. He said they were about the size of apple seeds, and still with edible rhizomes underground.

He experimented with various other crosses (H. mollis, H. grosseseratus, H. giganteus), but wasn't impressed with the results. Crossing annual sunflowers with perennials was pretty shaky, due to different numbers of chromosomes. Few seeds were produced from the cross, and even fewer were viable.

He did not cross with Jerusalem artichokes (he was going for seed yeild), but he said he's interested in doing some more work along those lines at some point.

He also told me that the Land Institute did some research a while back using the named Maximillian variety 'Prairie Gold'. They found through simple selective seed saving, they achieved these desirable results:

• Seed dormancy decreased. Without vernalizing the seed (storing under cool moist conditions to simulate winter in the soil) germination in the first generation was about 5%, second generation about 15%, third generation about 25%, fourth generation about 35%. This obviously was due to only growing plants from seeds that germinated, which selected strongly for lack of a need for vernalization.
  
  
• Seed shatter (seeds falling from the heads at maturity) decreased, due to the fact that the heads that shattered most had the least seed in the next generation.
  
  
• Seed size and weight increased. His seed cleaner was set to blow all unfilled and partially filled seeds away. Only filled seeds were part of the next generation.
  
  
• Seeds got darker. He didn't know why. There were some plants with lighter seeds, gray or brown (all seeds from a plant were about the same color), and striped and speckled. But the percentage of black seeds increased in each generation. He thought maybe the black pigment gave some resistance to weevil or seed moth damage.
  
  
• Yeild was directly correlated with branching and therefore number of heads.
  
  
• Flowering got earlier. In the original variety Prairie Gold, the bloom was very late and only half the heads might be filled when a hard freeze killed the immature plants. Selection for survivors gave earlier flowering, so the seeds matured before hard freeze.
  
  
• Flowering became more uniform in time. Date of first bloom changed less than date of last bloom.

That was all from my first brief email. I sent him some followup questions, and he generously responded again, and said he didn't mind my sharing his experience.

Here's the Q&A:
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Q: Are the seeds on the perennials edible?

A: They are edible. They taste just like domestic sunflower seeds. But they are small. Fresh squeezed sunflower oil is a good cooking oil or salad oil. Even lamp oil, though not the best, and it can be converted to biodiesel. It has been a while since I have figured how much oil per acre. At
900 poounds per acre of seed, and about 1/3 oil by weight (very optomistic), that would be 300 pound of oil per acre. And at less than 8 pounds per gallon (it is lighter than water, which is 8 pounds per gallon) That would be around 40 gallons per acre, plus a high-protein meal left over from the squeezing.
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Q: I guess I should say, are they practical as a (human) food source? (I'm thinking of the big annual sunflower seeds.) Maybe treat them more as a grain? Or are they better used for oil?

A: They are about 1/3 oil, 1/3 protein, and 1/3 fiber. But the hulls are like small sunflower seed hulls. If the hulls could be removed, sunflower butter, like peanut butter, would be the result. but removing the hulls is a problem. And bear in mind that the yield is way down in their second year, in most experiments.
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Q: Are the rhizomes a useful food souce (for humans)? Interesting to know that mice and other critters dig them up. I just recently realized that Jerusalem artichoke (sunchoke) was a relative.

A: The rhizomes are similar in taste to Jerusalem artichokes, but thinner. Think of asparagus, only thinner, maybe half as thick as well-grown asparagus.
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Q: I'm in Zone 5 (Central Ohio), so it does sound like maximilianii - salicifolius cross is the best starting point, based on your experience and my climate. Do they require supplemental nitrogen or any other fertilizers or nutrients?

A: An advantage to having mollis also in the population would be earlier bloom. Although using a maximiliani native to your area might give earlier bloom than the one I used. Sunflowers love nitrogen. Not as much as corn, but more than many seed crops. And perennial sunflowers spread if they are at the optimum plant density in their seedling year, they will be too thick their second year, and yield will be way down.

And something to bear in mind. Sunflowers are allopathic. That means they give off an herbicide from their roots. It doesn't kill everything, but it does kill cheatgrass (Bromus tectorum and B. Japonicum) and several mustards that are weeds here. And they will kill some other weeds by sucking the water out of the soil, and it gets up quick and shades other weeds. Experiments at the Land Institute showed that interplanting perennial sunflowers with Illinois bundleflower (Desmanthus illinoenses) improved sunflower seed yeilds. Bundleflower is a native perennial nitrogen-fixing legume. And it also has edible seeds, sort of. They taste terrible, but I guess they are good for you. They make good chicken feed. Bundleflower, unlike perennial sunflowers, can hold their yield for years. they are a taprooted perennial, so the number of plants gradually reduce over the years, instead of going up rapidly.
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So now I have another interesting long-term project. I guess I've got some seed shopping to do if we're ever not broke again.