All posts by Kathy Dice


Heartnut (Juglans ailantifolia var. cordiformis) is a type of walnut with a heart-shaped nut. All heartnuts are of the Japanese walnut species, or hybrids there of. The heartnut is a genetic “sport” or  mutation of the normal, wild type nut of Japanese walnut.

cracked shell and nutmeat of heartnut
Cracked heartnuts showing shell and meats.

Normal Japanese walnuts are cylindrical, elongated, rough or spiny, very thick-shelled and difficult to crack. In contrast, the heartnut is (more or less) Valentine-heart shaped and somewhat flattened. The heartnut is the easiest of all walnuts to husk and to crack. When moderate pressure is applied across the “shoulders” of the heart, the nut “pops” in two along the suture line, yielding two valentine-heart shaped halves. In cultivars with only “fair” to “good” cracking quality, the kernel breaks in half and comes out in two pieces. In the best cultivars, the kernel falls free from the shell in a single, unbroken piece – the only walnut in the world with this ability. On top of that, the heartnut is also the sweetest and mildest tasting of all the walnuts, beating out the so-called “English” walnut in taste tests every time. As if that weren’t enough, the heartnut has an incredible ability to store at room temperature.


Tom Wahl and Young heartnut
Tom Wahl standing by a 3 year old heartnut in Northern Arkansas.

The flavor actually develops in storage and peaks between five and eight years. Beyond 10 years at room temperature, heartnuts may become slightly stale, but not enough to keep them from being enjoyable.
The heartnut tree itself is incredibly fast growing. With adequate moisture and protection from weed competition they can put on six to eight feet of height growth per year in Iowa. The twigs are often as big around as broom handles. Leaves are compound and can be two to three feet long, with a very “tropical” look. Though the trees can become quite large, they tend to be low and spreading, like a live-oak. An old tree with a three foot diameter trunk and a 100 foot spread may be only 20 feet to 30 feet tall.
Heartnuts prefer moist, fertile, well-drained soil, though they will tolerate somewhat poorly drained soil better than most fruit and nut trees. They are best adapted to zones 5 and 6, with some of the hybrids suited through zone 4.
Superior heartnut cultivars can be grafted onto black walnut rootstock. The resulting tree can be twice as productive as seedling heartnuts or heartnuts grafted onto other heartnut rootstocks. Heartnuts are among the most challenging trees to graft, requiring great skill for success. For this reason, grafted heartnuts are very difficult to find in the nursery trade. More common are heartnut seedlings. The problem with seedlings is that they may grow into trees that bear nuts with no resemblance to those of their parents. Many heartnut seedlings “revert back to wild-type” – that is, their nuts will resemble the thick-shelled hard –to-crack wild Japanese walnuts. Some heartnut parent trees produce as much as 70% of offspring that grow into wild-type trees. On the other hand, the best heartnut parents will produce up to 90% heartnut offspring,

variations of heartnut shapes
Examples of various heartnuts from heartnut seedlings.

especially if they are pollenized by other good heartnut parents. If you are planting heartnut seedlings, you should plant about twice as many as the number of trees you want to end up with – that way, you can grow them up to bearing size, select the ones with the best nuts, and cull the poor ones.
Heartnuts are highly susceptible to walnut bunch disease. The disease is caused by a phytoplasma organism, and it’s transferred from tree to tree by leaf-hoppers. The disease causes “witches broom” type growth on the tree, and is frequently fatal. The good news is that the disease is apparently strongly linked to zinc deficiency in the soil. A foliar feed of the naturally occurring mineral zinc sulfate, applied in the spring, will usually clear up the disease in a single growing season. Zinc sulfate is applied to the soil around the drip line of the tree to prevent the disease from coming back.
Heartnuts have some great potential as a commercial tree. The unique shape of the nut alone makes them very attractive to consumers who eagerly pay $6 to $7 per pound for them. Add to this their rapid growth, heavy bearing, ease of husking and cracking, and great taste, and you have a tree that is well worth growing as a backyard tree or for a serious commercial venture. – Tom Wahl

Commercial Chestnut Growing Conference

Handouts from the Commercial Chestnut Growing Conference held on February 11, 2017 at Letts, Iowa

Iowa Chestnut Primer

Establishment of Chestnut Plantings with video of Tom Wahl’s talk.

Woodland Suitability Table (Because of multiple errors, Tom Wahl no longer recommend using the Woodland Suitability Table)

Mike Gold’s Chestnut Cultivar Handout and video of Mile Gold’s presentation.

All videos of the presentation are availabe at Red Fern Farm’s You Tube Channel

Details on the past conference:
Tom Wahl and Roger Smith are working together to provide a program on growing chestnuts commercially in the Midwest. It  will be held at the Letts Community Room in Letts, Iowa on February 11 from 9:30 am to 3:00 pm. Topics to be covered will include markets, cultural practices and economics. The outstanding potential for economic return of chestnuts will be stressed.

Chestnuts are a valuable nut crop that can be grown in a low-input, chemical free agroforestry system that includes permanent ground cover. Depending on soil types, they can be an excellent crop for land designated as highly erodible. Seedling chestnut trees of superior genetics can begin bearing nuts after 3 – 4 years on a good site and with good management. At 12 – 15 years they can produce 3,000 or more pounds per acre. In Iowa, chestnuts wholesale for an average of $2.60/pound.

The profit potential of chestnuts has encouraged the planting of chestnut groves throughout much of Iowa. Roger Smith, manager and owner of Prairie Grove Chestnut Growers, buys and sells chestnuts.  In 2016 he sorted, bagged and sold over 49,000 pounds of chestnuts grown in Iowa, Missouri and Illinois. He sees no end to the market potential of chestnuts and plans to plant an additional 25 acres of chestnut trees to his existing chestnut groves.

Speakers will include Roger Smith, Tom Wahl of Red Fern Farm, Drew Delang of the Natural Resource Conservation Service and Mike Gold of the Center for Agroforestry – University of Missouri. Preregistration is required. The registration of $20 includes lunch, snacks and a 26 page primer on growing Chestnuts in Iowa. Registration is available on line at .  For more information or other registration options call Kathy Dice at 319/729-5905. This program is being sponsored by Practical Farmers of Iowa, Iowa State University Extension and Outreach, Louisa County, Red Fern Farm and Prairie Grove Chestnut Growers.

You Pick at Red Fern Farm for 2016

 Pawpaws: We will have ripe pawpaws by mid September. Pawpaws are $3.00/pound when you pick them, $5.00/pound when we pick them. Bring buckets, boxes or crates. Ripe pawpaws are very soft and should not be stacked more than 2 deep. Call to schedule a time to stop by our house and we will show you the pawpaw patch. Weekends are very popular, so call early to reserve a time slot. Tuesday – Thursday is an excellent time to have the pawpaw patch to yourself. Picnic tables and portable toilets are close to the pawpaw patches. The grass will be mowed, but not as fine as a lawn. Be sure to wear sturdy shoes, prickly chestnut burs are scattered on the ground. Our orchards are in a rural setting, close to “wild” timber. Bring bug repellant. It only takes about 15 minutes to get 5 – 10 pounds of pawpaws. Late afternoon is the best time to pick, but ripe pawpaws will be available all day. Recipes are available.

Aronia berries: Aronia berries are available at 25¢/pound. They will hit the peak of ripeness during early September. We have over 2 acres to choose from, with some shade from young chestnut and heartnut trees. Call for more information. Link to map below.

Chestnuts: We offer you-pick under our chestnut trees. We provide tools and buckets for harvest and designate an orchard all your own to pick for a day. Picnic tables and portable toilets are close to the orchards. The grass will be mowed, but not as fine as a lawn. Be sure to wear sturdy shoes, prickly chestnut burs are scattered on the ground. The best time of day to gather chestnuts is late in the afternoon. Plan on coming after lunch and harvest up till sunset.

We have a very long waiting list of people who want to gather chestnuts. If you are new to our You-Pick, your name goes to the bottom of the list. If you can only come on a weekend, it may be years before you get a chance to gather chestnuts. If you can come on a Tuesday, Wednesday or Thursday you have a much better chance of getting to gather chestnuts. Call or email us to get on our list. We will call you when dates open up to see if you can come.

2016 Chestnut You-Pick Prices:
If you want to keep all the nuts you pay $2.50/pound for everything you picked up.  We discount that price by 25 cents if you come on a Tuesday, Wednesday or Thursday. On these middle of the week days the price is $2.25 pound.

If you don’t want all the nuts, we will sort the nuts by size and you will pay a higher price, but only take what you want.
Small: $2.50/pound,   Medium and Large: $2.75/pound,   X-Large $3.00/pound

And we will pay you 50¢ for each pound of chestnuts you gather and don’t take home.

Be sure to bring water and snacks. It takes about one hour for one adult to gather 10 – 30 pounds of nuts.

Maps and directions are available or call if you need help finding us.
But be warned, we are outside a lot this time of year . Be ready to leave a message.

Honeyberries – A New Crop for the Midwest?

Lonicera cearulea – blue honeysuckle, AKA “honeyberry”, “haskap” , and “mountain fly honeysuckle ” – by whatever name you call it, this plant is generating some excitement for its potential as a commercial crop.

Honeyberry cluster on bush.
Honeyberry cluster on bush.

The dark blue berries produced on small, multi-stemmed shrubs 2 – 6 feet tall are similar in size and flavor to blueberries. Like Aronia berries, honeyberries have 3 times more antioxidants than blueberries, but unlike Aronia, they taste good right off the bush. Growers report honeyberries sell out very quickly at farmers’ markets.

In the wild, honeyberries are found growing at the edges of wetland
s and in the shade of boreal (evergreen) forests across Northern Europe, Siberia, Northern Japan, and Canada. In the US they are found in the northern Midwest and in the NE from northwest Pennsylvania through New England. Honeyberries should not be confused with the exotic, invasive Amur and Tartarian honeysuckles. Honeyberries are not invasive; in fact, they need care and attention from humans in order to grow and thrive outside of their native habitats. Although they are cold-hardy to -50ºF, they do not compete well against grasses, and some are damaged by direct sunlight at southern latitudes.

Honeyberries originating from low humidity environments tend to be susceptible to the foliar fungal disease downy mildew.

In the wild, most honeyberry fruits are rather small, and flavor can be quite variable, from sweet-tart to bland or even bitter. In Russia and Japan, extensive breeding programs dating back decades resulted in the development of larger, better tasting berries on more productive bushes. In contrast, honeyberries were ignored in North America until quite recently, but brand new breeding programs by Dr. Maxine Thompson at Oregon State University and Dr. Robert Bors at University of Saskatchewan have already yielded some dramatic results. Cultivars producing better-tasting berries and more than twice the size of any in Asia are now available to growers in the US and Canada. Some of these new varieties are suited to mechanical harvesting.

Despite the rapid advances in the development of honeyberries, some significant challenges remain to be overcome before they become an important berry crop in North America. In the nursery trade, honeyberries of Russian origin dominate the US market. These Russian honeyberries bloom in March, well before the bees needed to pollinate them become active. This, pus their susceptibility to sunscald and foliar disease make this strain the least adapted to our latitude and climate. Worse still, some of the Russian cultivars were deliberately bred to have bitter-tasting berries for adding to Vodka. Some of these have found their way into the US market, leading some to believe the hype about honeyberries is fraudulent.

Honeyberries on bush.
Honeyberries on bush.

A great deal of work needs to be done to explore the limits of the honeyberry plant’s adaptability. “How far south can it be grown?” is a question that remains to be answered (current speculation is that zone 6 or 7 will be the limit). How much moisture do these plants need? Though they are found growing at wetland edges, it has been found they grow best in moist but well-drained soil. No one yet knows what the ideal ratio of shade to sunlight will be, or if this ratio will varyat different latitudes. Fertilizer requirements remain unexplored, except that N rates normal for blueberries can be lethal to honeyberries. Recommended plant spacing is just a guess at this point, and will be different for hand-picking verses mechanical harvesting.

One of the most serious problems facing this crop is the name. Many growers and researchers have adopted the Japanese name “haskap”. Others are using the name “honeyberry”. What you call a crop has a profound impact on its marketability. There are many examples of this, but one obvious case is the “Chinese gooseberry”. This plant was grown in the US for over 150 years, yet no-one was even interested in eating them until the name was changed to “Kiwi fruit”. It takes no explanation for why growers chose to replace the name “choke berry” with “Aronia berry”. “Honeyberry” is an excellent name for something you would expect to taste delicious. “Haskap”, to the ears of Americans, may refer to the lid for a special container for hazardous waste. Although I believe the name “honeyberry” will eventually prevail over “haskap”, I also think that the sooner we kill this name, the better.

Honeyberries are not well known in this country; in fact, most Americans have never heard of them. Much needs to be done to educate the public about this new crop, but I have no doubt that a native berry that tastes this good will have a bright future.  – Tom Wahl

Agroforestry – Comfortable Income from only 10 Acres

Sometime in December 2014 Tom Wahl made a claim on the Practical Farmers of Iowa list serve that 16 families could make a living farming on 160 acres using an agroforestry system. Below he gives more details on his claim. Edits have been added.

These figure comes from my own personal experience in growing and marketing chestnuts, plus yield data from the University of Missouri Center for Agroforestry and from Kansas State University. The full answer would be long and complicated. I am working on a book (to be published by Chelsea Green Co.) that will explain this all in detail, but for now I will give the “short” answer.
As you could probably guess, the most important component in my agroforestry system is chestnuts. I have been telling people for years that one reasonably fit adult should be able to manage 10 acres of chestnuts by his or herself (labor for harvesting being the limiting factor). 10 acres of chestnuts, well managed on a good site, should be able to produce 3500 to 4000 lbs per acre of nuts, for a total of 35,000 to 40,000 lbs on the 10 acres. This would be for a “mature” level of production, but that can be reached in 12 to 15 years from the initial planting. In Iowa, the nuts wholesale for $2 to $3 per pound, so the 10 acres should generate $70K to $120K per year.

Chinese Chestnut tree loaded with burs.
Chinese Chestnut tree loaded with burs.

That is just for chestnuts. You could put a pawpaw tree underneath every chestnut tree. Pawpaws are natural understory trees and can produce 50% to 75% of a full crop even in fairly heavy shade. Dr. Patrick O’Malley estimates that pawpaws in Iowa should bear around 14,000 pounds per acre (in full sun). Pawpaws can wholesale for as high as $7 to $10 per pound. [we plan to sell you-pick pawpaws for $4.00/pound in 2015] Under the pawpaws and chestnuts you could add shade-tolerant berry shrubs such as gooseberry, currant, and honeyberry. On the ground, in the more exposed areas, you could grow perennial vegetables such as asparagus, rhubarb, and horse radish. In the shadier areas you could add high-value medicinal plants such as ginseng and goldenseal.
Even though this takes 12 to 15 years to reach this level (and that is assuming no disasters such as extreme weather events), this does not mean there is no income leading up to this point. Chestnuts can begin bearing in as little as two years from planting, and can reach 350 lbs per acre by year 5.
I am sorry that I can’t point you to university research documenting all of these figures, but there just aren’t any universities doing this. The best university info on agroforestry comes from U of Missouri Center for Agroforestry, including a 12 page summary on chestnut growing. – Tom Wahl

Table 1 shows a conservative projected production and income for chestnuts assuming 108 trees/acre and $2/pound selling price.

Year of growth

Pounds chestnut/acre

Gross income/acre


0 0
4 56



432 $864
10 1,512


15+ 3,348


Table 2 shows a conservative projection for pawpaws assuming 108 pawpaw trees/acre (growing under chestnut trees) and $5/pound selling price.

Year of growth Pounds pawpaw/acre Gross income/acre
1-6 0 0
7 216 $1,080
10 756-972 $3,780 – $4,860
11 864-1188 $4,320 – $5,940
14 1,404-1944 $7,020 – $9,720
15 1,620-2,160 $8,100 – $10,800

Uncommon Fruits with Backyard or Commercial Potential

Let me tell you a story. The Chinese gooseberry, Actinidia deliciosa, a perennial vine native to eastern Asia, was grown as an ornamental for centuries. Even though it produced a fruit, few people consumed it and it was never found in the market. A few decades ago some enterprising New Zealanders decided to take the Chinese gooseberry commercial. They changed its name and came up with a marketing campaign. Today, kiwi is popular all over the world.   

There are thousands of fruits around the world that are seldom or never found in commerce. Of these, dozens – perhaps hundreds – are well suited to backyard culture and home use. Some of these could become commercially popular if more people knew about them. One example is Actinidia arguta, the hardy kiwi.  Hardy kiwi fruit is a smaller (about the size of a grape), sweeter, and mHardy kiwi fruit held in a hand.ore flavorful relative of the fuzzy kiwi found in stores. Its smooth skin does not need to be peeled. The vine is vigorous to the point of being rampant, requiring a very sturdy trellis to support the fruit load of up to 200 pounds per vine. They come in male and female; males produce no fruit, but are required for fruit production on females.

Another little known fruit with potential is the goumi, Eleagnus multiflora. This small tree or large shrub is a non-invasive reGoumi fruit held in a hand.lative of the invasive pests autumn olive and Russian olive. The potentially heavy crops are sweet-tart and cherry like in size and flavor, but without the pest and disease problems associated withcherry production.  It is hardy through zone 5.

Che, Cudrania tricuspidata, sometimes called “melon berry” or “silk thorn” is a Chinese relative of our native Osage orange. Che fruit resembles Osage orange, but is only 1” – 2” in diameter and deep red when ripe. A more important distinction is that while t

Che fruit on bush.
Che fruit on bush.

he larger Osage orange is inedible, the fruit of the che is chewy but delicious. The flavor is said to resemble a mix of mulberry and fig, both of which are related to che. Though it usually only reaches the size of a large shrub or small tree, che can produce up to 400 pounds of fruit. The long growing season required to ripen the fruit limits the production to zone 5b and south. Development of earlier ripening cultivars could potentially extend its range northward. Like the kiwi, che comes in male and female, but unlike kiwi, some female che will bear seedless fruit without a male nearby.

The Cornelian cherry Cornus mas, is not a cherry at all, but a type of dogwood native to Europe and Asia. Like the goumi, it can produce very large crops of bright red, sweet-tart fruits on

Cornelian Cherries
Cornelian Cherries

a large shrub. The fruits are similar in size and flavor to pie cherries. Also like the goumi, it seems to be unbothered by pests and diseases. Even Japanese beetles seem to leave them alone. They are cold-hardy though zone 4.

A close relative of Cornelian cherry is the kousa dogwood.  In early spring it is covered by large, showy white flowers like our own native flowering dogwood, but on this eastern Asia native the floKousa fruit in hand.wers are followed by edible red fruit. Kousa fruits are highly variable in size, flavor and quality. The best of these have a creamy texture and a sweet flavor reminiscent of paw paw. Unfortunately, kousa varieties are usually selected for ornamental qualities. One single cultivar, ‘Big Apple’, has been selected for large fruit size. So far, no kousa varieties have been selected for fruit flavor or quality.

Mayhaw is a term applied to hawthorns, Crataegers sp., that are highly prized for their fruits. In the stricteMahaw fruit in hand next to jar of mayhaw sense, mayhaw is C. aestivalis, a species native to the southeastern US. Mayhaw fruits are small, bright red, tart, but rich tasting. The shrub or small tree can tolerate a very wide range of conditions but is usually found on wet or even swampy sites. The mayhaw flowers and fruits very early for a hawthorn. In the Deep South, fruits ripen in May, hence the name. Devoted fans of the mayhaw claim it makes the very best jelly in the world.

More broadly, “mayhaw” may be applied to any of several other species of hawthorn with high quality fruit. Most of these are native to the northeastern US and their fruits ripen in the fall. Arnold hawthorn, C. arnoldiania and scarlet hawthorn, C. pedicellata are a couple of the better known hawthorns with commercial potential.

Medlar is a relative of hawthorns, apples and pears. The fruit of this Eurasian shrub or small tree was one of the most commercially important in Europe during the Middle Ages, but has since faMedlar fruit on treellen into obscurity. The mature fruit is brown, hard, 1” – 2” in diameter, and somewhat resembles a small apple or pear, but with a very large calyx or “blossom end”. This characteristic gave rise to the fruit’s old common name “open arse.” Mature fruit are too hard and astringent to eat. They must first go through a process of over-ripening called “bletting.” When they reach the point of becoming mushy, fully bletted medlars take on a flavor and consistency of applesauce spiced with cinnamon. To eat the fruit you bite a hole in the tough skin and suck the pulp, using your teeth to strain out the large, hard seeds. It is no wonder the fruit has fallen out of favor, and it is not grown commercially anywhere in the world today. Where i
s the commercial potential? Certainly it is not with the general public. On the other hand, even in isolated rural areas you can find groups of people who will spend hundreds or even thousands of dollars to dress up in Medieval costumes to attend “Madrigal Dinners” or “Renaissance Faires”. Just imagine what you could charge if you were the only supplier of authentic bletted medlar fruit to su
ch an event! – Tom