Hybrid Hazelnuts Combine Best Traits of Wild American and European Varieties for Northern Farmers

Feb 12, 2020

Growers and farmers from around northern Minnesota are invited to a free meeting at Central Lakes College in Brainerd on February 25th to find out about the potential of growing a new crop: hazelnuts. These are not the hazelnuts that lots of us find growing wild in our forests and fields. These are brand new hybrids that can be grown as a cash crop.

On the Northern Community Radio’s Wednesday Morning Show, Maggie Montgomery spoke with Lois Braun, a research scientist at the University of Minnesota, about the potential for growing hazelnuts. She asked Lois to introduce us to the new, improved hazelnut.

Lois Braun: As I go around meeting people, a lot of them tell me, “Oh, hazelnuts are my favorite type of nut. I love hazelnuts.” Most of them are talking about European hazelnuts that, as their name implies, come from Europe. They grow mostly around the Mediterranean region of Europe, which, if you know anything about climate, you know that their climate is not anything like our climate. The hazelnuts that you can find in grocery stores are most likely either imported from Europe or even Asia. A lot of them come from Turkey. Turkey is the world's leading grower of hazelnuts. Or they come from the Pacific Northwest, which has a Mediterranean-type climate.

The largest grower of hazelnuts in the United States is Oregon. Those hazelnuts are not winter hardy in Minnesota. And likewise they are highly susceptible to a disease called the eastern filbert blight that is endemic to the eastern half of North America. So we've got European hazelnuts and American hazelnuts. The American hazelnuts are broadly distributed in the eastern half of North America, but they have much smaller nuts, and proportionally thicker shells. On the positive side, they are also resistant to eastern filbert blight and obviously adapted to the climate.

There are actually two kinds of native hazelnuts in our region. There's the American hazelnut and then there's the beaked hazelnut. The beaked hazelnut has a husk, a very fuzzy husk with a long, snout-shaped protuberance from it. We're not dealing with the beaked hazelnuts at all.

The hybrid hazelnuts that we're talking about are hybrids between the European hazelnuts and the American hazelnuts. They were hybridized to take advantage of the positive attributes of both kinds of hazelnuts. That is, the winter hardiness and the disease tolerance of the native hazelnuts combined with the larger nut size and greater shellability of the European hazelnuts.

The crosses were actually made back in the 1910s, 20s and 30s by a lot of different people. But here in the Midwest, the most notable person was somebody called Carl Weschcke. His work was picked up by somebody called Phil Rutter, who still lives today. He has been developing them at his farm down near Lanesboro in southeast Minnesota.

About a decade ago - actually in 2006 - the University of Minnesota, in collaboration with the University of Wisconsin and some folks in Iowa as well, started going around to all these farms. A lot of people had bought hazelnuts from Phil Rutter; they had bought seedlings. The thing about seedlings is that each seedling is genetically unique. What that meant was that all these hazelnut plantings - hybrid hazelnut plantings on farms - presented a plant breeder’s paradise in terms of a lot of genetic diversity and ability to select for plants that had the characteristics that we need for a commercially viable crop.

The nature of seedlings is, as I said, genetic diversity. Many of you have probably heard that apples won't breed true. You can take the seeds out of the Honeycrisp apple and plant them and grow an apple tree, but it won't be a Honeycrisp apple tree. Half of its genes will come from Honeycrisp and half of its genes will come from whatever other apple tree pollinated that particular seed. The seeds that come off one apple tree might have gotten their pollen from a whole bunch of other different apple trees and consequently they will be as diverse as a as a litter of feral kittens. Some of them will be great and some of them will be not so great at all. Most will be mediocre.

That's the way it was on these farms where we went and found these hazelnuts growing. By and large, the farms did not have bushes that were productive enough to make a viable crop, but there were still a few plants on those farms that were outstanding. So we tried to identify those plants, and we propagated them vegetatively by a method that I s not grafting but analogous to grafting so that we'd get genetically uniform plants. We put them in replicated trials because it's only when you put things in replicated trials that you can know whether the cause of their excellence is due to genetics or it’s due to growing conditions.

With uniform growing conditions we had three genetically identical plants each at each of five trials, and the trials were uniform within the trial, but diverse between the trials. At the end of about eight years of looking at these plants, we started to see clear patterns of which ones were best and which ones weren't.

The stage we’re at right now is the stage of being ready to disseminate those best plants to people out on farms because we want to test them in more different environments just to verify that they really, really are as good as we think they are.

Our big bottleneck is ability to propagate them because, unlike apples, we can't graft them. So far we've been using a method called mound layering, which is actually an ancient technique. It involves getting stems from the ground. Hazelnuts are multi-stemmed bushes. If you cut them down (that's a process called coppicing) and pile sawdust over them - you'd have to do a few other things to these stems that are emerging from the ground in response to being coppiced – and pile sawdust over these new stems, they will grow roots into the sawdust. Then you can take each stem as a new plant.

So we've been doing that to try and get more plants. It's a very slow process because each plant that we start with can only produce from five to 10 or maybe 15 or 20 new stems. Each mother plant can only produce a limited number and the mother plant has to be 4, 5, 6 years old before we can do that process to it. Obviously, we're not going to multiply them very quickly.

Although our research has been built on that method, there is another method called micro propagation, which involves taking a very, very small segment of young succulent green tissue and putting it on a sterile petri dish and giving it all the hormones and the nutrients it needs to survive, growing it in ideal conditions. The cells multiply and produce new little plantlets. The only problem is that hazelnuts don't like the process very well.

So we've been trying to propagate them and having a lot of frustration in getting the system to work, but we think we’re finally going to have some plants. Initially we’ll probably have about two or three selections but in a couple of years we think we’ll have many more selections.

Maggie Montgomery: What kind of habitat do these new hazelnuts require?

Lois Braun: What we've observed and, given that we've grown them in a limited number of places so far, what we've observed is that in the wild populations in the upper Midwest, seem to be most abundant in the piney woods of central into northern Minnesota and Wisconsin. However, we've heard a lot of reports of abundant hazelnuts further south in the more loamy and heavier soils. We're not sure whether the distribution in central Minnesota is simply because agriculture has not ripped them out or whether it's because they're more adapted to those sandy, less nutrient-rich soils. It could be some of both. What we do know is that we see abundant hazelnuts on sandy soils. But observations are that they actually grow better - grow faster, grow bigger - if they are on richer soils that retain moisture.

Maggie Montgomery: We have American hazelnuts around our place. When I think about harvesting them, it's a race between me and the chipmunks and the mice, and then there are little worms that can get in them. How do the people growing hazelnuts - these big, nice hazelnuts - are they going to have those same kind of issues?

Lois Braun: Yes. But when it's your crop, you're more focused on it. And yes, lots of people tell me that they only find wormy ones. The explanation for that is that squirrels and mice have an acute sense of smell and they know when those nuts are almost ready. They are out there all the time but we're not. So the squirrels and the mice and the blue jays and the crows and the turkeys and probably raccoons and bears get those nuts before we do. They can also distinguish between the ones that have worms and the ones that don’t. They leave the ones that have worms behind so when we get there we get the impression that they all have worms whereas initially they didn’t all have worms.

Maggie Montgomery: I also imagine that switching from, say, row crops to a perennial crop like the hazelnut would be good for the soil. What are the environmental considerations of growing hazelnuts?

Lois Braun: That in fact is a large part of our impetus. They are obviously perennials, and they're long-lived perennials. We don't actually know how long they will live, but our speculation is about 50 years. So that means they don't have to be replanted every year. And one of the most destructive aspects of agriculture is simply tillage. If you look around at native environments, they are not plowed every year. Especially not our forests, but our prairies weren't plowed every year either, and neither were our savannas.

So what happens is those root systems in the ground, they are constantly pumping atmospheric carbon into the ground. When those roots die - and the whole plant doesn't have to die in order for the few roots to die - it's kind of like, you know, above ground leaves die, branches die. The same thing happens below ground. That carbon is food for a whole complicated ecosystem of other organisms - fungi, bacteria - insects that eat the fungi and bacteria. Altogether, they build soil organic matter, and soil organic matter is what makes a good, healthy soil with good tilth.

And also they suppress diseases. Perennial ecosystems, if you look out at the natural forests, they survive pretty well without us. The roots also hold the soil, protect the soil against soil erosion which, in turn, not only is it good for the soil but it’s also good for our waters. Because we don’t have soil or soil nutrients leeching into our waters or running off into our waters, making muddy waters like you see in so much of southeast Minnesota. The rivers run brown in southwest Minnesota as well. The rivers run brown. They're contaminated with nitrates.

So as best we can tell, hazelnuts have root systems that really suck up the nitrates and keep them out of our water system. I do say the best we can tell because we have not done direct research with our hazelnuts. So we're basing this on research done with other plants. Eventually we hope to be able to do that research. But there's only so much research we can do at one time.

What I can tell you, though, is that very early on in my research I was involved in digging up a mature hazelnut bush at Phil Rutter’s farm. We went down nine and a half feet before the roots ended. In fact, there was still one little root that we were tracing down further. But we were getting tired digging, so we declared the bush to be the winner on that one.

Maggie Montgomery: Growers who are thinking of getting into growing hazelnuts will be doing something that's pretty new. What's going to happen at this meeting?

Lois Braun: Well, I will go into a little bit more detail about what I just stated and also a little bit more about what is involved in growing them. For example, how do you get ahead of those squirrels and blue jays? How are they harvested? How are they dried? How are they marketed? What kind of weed control and fertilization do they need? And where can you get the plants? How many plants? Things like that. We’ll go into those kinds of details and gauge how much interest there is.

Our ultimate, or I should say our proximate goal, is to develop networks of growers. We've been calling them clusters – locally-based clusters of growers who can learn from each other as they start this new venture. We don't recommend that anybody go out and plant 10 acres of hazelnuts without having gotten their feet wet by planting just a few to start with to see if it really is a crop that they are interested in. But with any new crop, you need to develop infrastructure to deal with them.

Hazelnuts, because they are a nut, they grow in a shell. They have some processing requirements. So a lot of people ask me, “well, what about pick-your-own?” And my answer is they're easy to pick, but they're not so easy to shell. So pick-your-own is probably not going to take off unless you also have an on-farm processing facility where people could take the nuts they've just picked and process them.

But actually there are some significant barriers that would make that probably not-so-feasible. The equipment costs could be rather high initially, but they could be a lot more doable if growers work together; for example, to develop a processing facility within their region so they don’t have to travel a long distance, The model for this is the local creamery.

Maggie Montgomery: As a hazelnut lover, I wish you every success. And also the farmers because this is a challenging time to be in farming. There are always some risks, but also some rewards in trying something new. So good luck with your meeting.

Lois Braun: Well, thank you very much!

The hazelnut meeting is Tuesday, February 25th, from 1 to 4 p.m. at Central Lakes College in Brainerd. RSVP required if you’d like to attend: mnhazelnuts dot Eventbrite dot com.