I am trying to grow hazelnuts in the south, DFW Texas so...very south. I have purchased some OIKOs trees initially (Precocious , ECOS and Select One) and planted them 4 years ago, and another batch planted 3 years ago. I also got a wild American hazel from ebay, but can't recall where it was from in the country. I have also been growing a Barcelona during this time. Year 3 I started getting nuts from some Precocious plants, just a few. Year 4 I got some more from my oldest Precocious and some from the wild American a small handful of each. This year my other younger Precocious plants have flowered with more female flowers than ever before so hoping for a bigger handful of nuts. But based on flower numbers at best I could get about 50 nuts. My wild American flowered more this year with maybe 20-30 female flowers. Only now I am getting a few flowers from the 4 years old ECOS, and a couple on the Select One. Do not take this as one is better than the other as I have had to learn how to coddle these in the brutal Texas summers and had some issues with some plants for various reasons. About 2 years ago I started planting fungus resistant varieties of Europeans including Jefferson, Felix, York, with this year adding Yamhill. The Europeans are too young to know if they will work so won't mention them further here. The OIKOS ones I have planted in full sun or mostly full sun, and a couple in part shade. Even now I don't have a handle on all of this but a few observations that may be relevant to other southern growers. I am getting relatively few male catkins. Not enough to wind pollinate, so I literally have hand pollinated every flower. I am sure I would have got no nuts given how few catkins I had if I did not hand pollinate. Maybe in the future I will get the larger numbers of catkins for air pollination, but I am not sure. I am getting more female flowers than catkins. So for southern growers, perhaps this might be an issue? Also with the TX hot, typically dryer summer, I have to irrigate to keep them happy. They will survive without it, but tend to limp along. But even with good irrigation I get leaf burn in the high summer and lose some leaves (doesn't defoliate) then the leaves grow back at the end of the summer. If the male catkin issue continues then I will simply hand pollinate those tiny female flowers. If I start getting more catkins I will give the wind a shot. Things do seem to be moving in the right direction at least with female flowers with 2X more than last year so I am optimistic I should get the Americans to yield me a modest harvest of nuts in a year or two from a total of 9 plants. Note that the nuts so far are from Precocious and the wild American. Select one flowered this year for the first time probably cause it is small as I had to transplant. ECOS is as big as my Precoucious but it has only put on 3 female flowers this year a first. Whereas the Select One which is a third smaller in size put on about 8 flowers. The next year or two I should really have a feel for how productive the Americans will be. The fungus resistant Europeans should start some flowering in the next year or two based on current size. The one exception is Barcelona (fungi susceptible) finally put on a handful of female flowers on a 5 year old plant. That plant has suffered from my learning curve and probably disease pressure but is still alive but I have not got nuts from it yet nor seen flowering till this year. Conclusions so far, some American varieties can produce at least some nuts in the punishing Texas summer. Now the question is can I get a lot. Too early to tell.