I've been wanting to plant some sunflowers to use as a trap plant for leaf-footed bugs. I had a blank spot in the garden layout where I could plant a small plot of them. We're talking something like a 3'x 8' plot. This would be in the same row as the tomatoes but with some pepper plants in between them. I'm not really worried about the distance or orientation of the sunflowers to the tomatoes, I figure whatever bugs they'll draw away from the tomatoes will be a "plus" for me.

Anyhow, the big factor for me is that they are allelopathic, creating biochemicals that suppress or prevent the growth of other plants. I've read the "sunflowers suppress/kill other plants" and the "I've never had a problem with sunflowers..." arguments and statements and I'm more confused than ever. In all of this the "science" of it still points to the fact that sunflowers are allelopathic and indeed can the seed hulls, stalks, roots, leaves, the entire plant supposedly contains a chemical that can suppress the growth of many plants.

I try not to do anything that might hinder a healthy, growing garden (I know I fail a lot, but...). Some of you may know how picky I am about things...to a fault, at times. Anyhow, we have heavy pressure from leaf-footed bugs and I've thought in the past of using sunflowers as a trap crop. I just don't want to put something in the garden that might be a plant suppressant...another wildcard variable to figure out "why this didn't grow well".

Do any of you plant sunflowers throughout your garden? I figure I'd have the small plot of them in a certain spot and move them to another spot next year. Naturally a vegetable would follow the sunflowers that year. An option would be to till a small area outside of the garden plot and grow a strip of them there...that would kind of complicate my grass mowing within the fenced garden area, but it could be done.

And lastly, Peredovik sunflowers are the recommended cultivar for a trap crop but I see many recommendations of simply "black oil" sunflowers. The little packets of sunflower seeds are expensive but I get the big bags of Pennington black oil sunflower seeds for the birds...they have "Bird-Kote" on them, some type of vitamin supplement. But, I've heard people state that they germinate well. I can't find where Pennington states which cultivar it is that they use for the birdseed, but it seems that Peredovik is an often grown crop and that if nothing else the Pennington BOSFS is a first or second cousin of Peredovik seeds. Anyhow, I'm thinking about planting some of these birdseed seeds and see what happens. One thing, though, is that I haven't seen any sprout around the base of the bird feeders but it may be that the squirrels and chipmunks make short work of the seeds that fall to the ground.

Ok, I just had a bright idea (anyone see that little wheat lamp turn on above my head? ). I rolled up 25 of the Pennington seeds in a damp paper towel and stuck them in a ziplock baggie. I'll see what their germination rate is.

Speaking of germination rates...I've got a big box of zinnia seeds I harvested from two years ago I need to test.

Anyhow, what do ya'll think about sunflowers in the vegetable garden? Problem? No problem?

Ed

I sometimes use sun flowers on the border. They are pretty and invite finches. Never saw any effectiveness as a trap plant. They do do have two drawbacks.1 they do suppress the growth of many plants planted within 4 ft. 2 they are usually big plants which shade smaller plants. Lima beans seem to tolerate them, My father use to plant the large Calico limas in a row of sunflowers in place of bean poles. I usually plant the multi blooming decorative types rather than the large headed type. They also have better colors.
As for the leaf footed bugs, they are major problem for me only on Okra. I turn out a couple of Jimson weeds on the borders as a trap plant. I then spray the Jimson weed which are a leaf footed bug magnet. Note that trap plants are usually magnets for some some type of destructive insect. If you don't use insecticides on the trap plant, all you accomplish is breeding an extra large herd of your enemy bugs.

Thanks for the feedback, Dillard. I think I'll leave them out of the garden plot...maybe plant some outside it's perimeter. But, what you said about spraying the trap crop or either raising a bigger herd of hungry bugs also makes me take note. I'm no fan of spraying anything. I was reading about the leaf-footed bugs and it seems that crepe myrtle trees are hosts for them, too. We have several of those around the house...we have lots of privet hedge here and there, too, but don't know if that's a host or not. Ah well, I'll probably end up planting my zinnias (you've gotta love all the butterflies!) and leave the sunflowers out of it. I appreciate you keeping me from making gardening harder for myself!

Just in case anybody is curious about the germination test I'm going to let it run and see what happens.

in any direction for the large sunflowers, a little less for the small ornamental varieties. They have a large root system.

Delete

I stopped growing sunflowers for a reason, now I know.

On the other hand, of course, they'll keep the weeds down!

Here's something strange and don't you dare laugh! I'm 67 years old but those very tall classic sunflowers make me feel a bit uneasy looking at them. Even at pictures. Maybe I was afraid of sunflowers when I was little and I just don't remember. Okay, you can all laugh now!

Looming! Eeeek!

Deeby said:Looming! Eeeek!

Yes, and with an evil grin.....

Other than the fact That these things grow to the size of small trees an provide a lot shade and eat up a lot of nutrients and water, They are not detrimental to plants. Be careful if there are small children around, the seeds are toxic.

They are toxic. I read from a true detective story that a wife poisoned her husband that way. I think she was a doctor, that's how she got her knowledge.

They are Ricinus, the source of ricin, as in that white powder that was being sent through the mail to politicians and such.

They also are the source of castor oil. The product is in the processing. The raw beans are dangerous especially to children, who like to put objects in their mouth. These are just the right size to entice them. It is estimated that the lethal dose for adults varies between 5-20 raw beans, either crushed by chewing or mechanical means.

Scary!

Interestingly, while Ricinus isn't allelopathic as a plant, it is understood that aqueous extracts of the leaves and pericarp, which is the shell holding the beans (as in, drying them and brewing sort of a tea with them) will very effectively prevent germination and growth of other plants. Might be smart not to throw them in a compost pile.

Actually, the beans aren't poisonous if unbroken. Don't chew them, and you'll be fine!