The American Chestnut: Tragedy, legend, salvation through GMO technology

The very essence of the American Chestnut is one of tragedy and possible salvation from the dirty little phrase GMO.  The once mighty King of the American forest of the eastern United States was all but decimated by 1960, with a few small stands in Maine, Pennsylvania, New York and southern Appalachia.  The tree was once the very essence of Americana, used as lumber, a food source, honey and by-products such as tannin for leather production and silk dying.  Furniture, homes, barrels, railroad ties and fences.  American Chestnut was the tree of everyday lives.

American Chestnut Blight in Adams, MA.

It was not devastated from over-harvesting, clear cutting or other indiscriminate lumbering processes, it was however destroyed at the hands of man, unknowingly.  It was with the introduction of the American Chestnuts cousin, the Chinese Chestnut that was its demised.  Early in the 19th century Chinese Chestnut was imported to the US as an ornamental addition to urban landscapes.  Unknown was that the Asian cousin carried a fungus that it was genetically immune to and in 1904 it was first identified at the Bronx Zoo, called the Chestnut blight.  Within 50 years almost 4 billion American Chestnut trees had been killed in over 200 million acres of eastern forests.

These once titans, stood 100 feet tall and 10 feet  in diameter were reduced to a few feet tall and certain to die within the first 10 years from the fungus, which attacks the bark and girdle the tree causing it to die, usually within a year of being infected.  Sadly there has been no way to kill the fungus.

The importance of the American Chestnut is often over shadowed by it's benefits to humans but it's importance in the forest should be looked at as well.  They are a fast growing tree, able to bear fruit (nuts) in the first 3 to 7 years, and they continue to do so consistently, unlike its sister, the Oak which will not bear fruit for at least 10 years and they do so inconsistently, making them an unreliable food source for wildlife, and commercial harvest.  The tree is a biomass master.  It contains more nitrogen, phosphorus, potassium and magnesium in its leaves when compared to other trees that share its habitat. This means they return more nutrient to the soil which helps with the growth of other plants, animals, and microorganisms

Despite its decimation as a lumber and nut-crop species, the American chestnut has not gone extinct. The species has survived by sending up stump sprouts that grow vigorously in logged or otherwise disturbed sites, but inevitably succumb to the blight and die back to the ground. The most recent USDA Forest Service survey for New York State indicates that there may be as many as 60 million of these sprout clumps in New York State, a rich gene pool for starting a restoration effort.

In the early 80's the USFS, USDA, and the State University of NY College of Environmental Science and Forestry quietly began working on making the American Chestnut something more that the scrub shrub it had been reduced to and as of today there are more than 10 other organization working to return the American Chestnut to it's place as the King of Tree's.

How is that happening?  Through genetic modification of the American Chestnut.  Currently all test stocks (none have been planted outside of test areas) they consist of 1-2% Chinese Chestnut DNA to the 98-99% American Chestnut DNA, all of this is through what make many cringe, GMO processing techniques, backcrossing as it is commonly called.  By backcrossing the American chestnut with Asian chestnuts (which are naturally immune to the blight), the goal is to create an American chestnut that is blight-resistant but almost completely American, with all the strong qualities of the majestic trees of a century ago.  Some might argue that backcrossing is not creating a GMO, but in literal term it is and backcrossing is a processes farmers and gardeners alike have used for ever.  Officially it is estimated that professionally backcrossing started  about 1918.

So hopefully within the next 5 years we will see the first reintorduction of Blight resistant American Chestnut, but it may not be in our life time that we will ever seen the forest filled again with the King of America, the American Chestnut.

Mosquitoes and rain barrels

So if you are like me you have a 5 gallon pail, 30 gal barrel or a 55 gal barrel collection rain water to tend to the garden or even your lawn.  And with the rain we have had in the past two weeks in the Capital District, it only takes a short time to fill them up if the are attached to a gutter.  It also takes even less time for mosquitoes to turn around and create a filled drum of larva.

Not something we want to see, or have.  So what to do to keep those pest at bay?

If you are attached to your gutter system to collect rain water, you will first need to make sure the gutters are properly pitched to prevent standing water to build up in your gutters.  It takes only a tablespoon of water for a mosquito to make it a breeding ground, then when it rains those little larva now are washed into the collection system.

There is also a school of thought, and I will cover that now so that we can get on to some other solutions and that is to add bleach to the barrels.  The problem with that is that there is a fine line to sterilizing the water with bleach and making it a dangerous water mixture that will kill your plants and bacteria in the soil.  With chlorine bleach there is a safe amount to use to make water safe to drink and if you use to much it could make you very ill or even cause death.  You also need several hundred gallons of water to measure correctly.  That being said you also need to let the water be exposed for 24 to 48 hours to UV lighting to "burn off" the chlorine.  If you mixture is wrong...it could still be dangerous for the soil and plants or if the exposure and mix were off the mosquitoes will be right back there.  A tough catch 22 so we advise to makes sure any product you use does not contain any chlorine bleach...period.

So here are some ways to curb mosquitoes in your rain barrels:

1. Put a goldfish or two in the barrel. I especially like this one because of the happy little ecological world it creates. The fish eat the mosquito larvae and then poop out beneficial elements (mainly, nitrogen) for your garden. Things to remember: leave enough of an opening so that the fish can receive oxygen from the surface, and take the poor guys out before the first frost!

2. A thin layer of vegetable oil on the surface of the water can prevent mosquito larvae from clinging to the surface, which is how they breathe. The oil slick will also serve as a barrier for insects to enter the water. Do not use this method with goldfish because it blocks the availability of oxygen also remember that if your barrel over fills, the oil will run off.  This method is best if you do not use your barrel water regularly and it may sit for a few days before the the next rain.

3. Filters - cover the intake with a piece of old nylons or netting. You will need to clear out the filter regularly and ensure that there are no holes for insects to pass through.  This would also include adding a screen or old sheet cover to your rain barrel.

4. Barley Mosquito Dunks - read the labels carefully, not all dunks are chemical free and I can not promote a specific manufacturer.  I am still searching for a How to, so you can make your own but one I do have requires a cup a just harvested barely, the whole plant, minus the roots, lightly shredded and place in a stocking or cheese cloth, tied up and thrown in to the rain barrel.  As it breaks down in the water, Bacillus thuringiensis israelensis (Bti) is released, this is toxic to the larvae but safe for everyone else.

Love to hear your suggestions as well.

How to grow your own tomatoes

Modern Farmer is one of my favorite publications and it is produced and written locally right down in Hudson, NY.  I wanted to capture a 3 part series on growing tomatoes because lets face it, nearly all of us grow them.  This series will help you make your tomatoes a little more successful.  Be sure to follow Modern Farmer or possibly subscribing to their periodical.

Tomatoes, according the National Gardening Association, are the most popular vegetable among backyard gardeners. Their 2014 survey found that 1 in 3 American households have a vegetable garden and that nearly 9 in 10 of those gardens include tomatoes.


Part 1: Starting Seeds Indoors

Growing tomatoes from seed isn’t hard, but there are a few things to be aware of. As with all things agrarian, timing, genetics and environment have to be in alignment to reap the rewards of your efforts.


Part 2: Transplanting

To help them along, there are two things you need to do before you transplant your seedlings: Prepare the soil and something gardeners call hardening off.

Part 3: Staking, Training and Pruning

Tomato beds have an unfair reputation as the messiest, ugliest, most disease-ridden parts of a vegetable garden. To keep them from devolving to this sorry state, tomato plants need your care and support.

How to Plan an Orchard, or at least get started....

There are few things finer in life than going out of your house on a summer’s morning – perhaps holding your child by their hand – to pick the fruit you will eat with your breakfast. Plucking a ripe pear or a crisp apple from the branch, savoring its aroma and looking forward to the fresh, deep taste that comes from cultivating crops in harmony with nature is a wondrous thing.

Most permaculture gardeners with sufficient space will include at least one fruit tree in their garden design. It can provide a focal point in a small suburban plot, or even, if a dwarf variety, add variety to a courtyard garden. Fruit trees are typically the centerpieces of the common permaculture planting technique of guilds, and they bring a lot of benefits to any site, from shade to protect plants and deep roots to improve the soil structure, to attracting birds to the garden and, of course, providing a crop for eating.

For those with more space, an orchard can be a very attractive option. Indeed, orchards are arguably the most likely legacy of your permaculture garden, as with a little care and attention, they will provide fruit for years to come. While the specific attributes of your site and local climate will ultimately influence your choice of fruit trees and the location of your orchard, there are some general guidelines to consider when planning an orchard on your permaculture plot.

Site
Orchards are typically a design feature for Zone 2 of your permaculture plot.

Requiring less attention than the vegetables, herbs and fruits in Zone 1, they will still benefit from attention every few days – to check for any potential pest problems or to see if wildlife has been able to access the orchard, for example. You will visit more often when the crop is ready for harvest, and if you allow livestock such as pigs to forage in the orchard, you will want to check on them every day to ensure their needs are being met. However, once established, orchards need very little actual maintenance; with the correct planting when instituting your orchard, it should pretty much take care of itself.

Orchards need a lot of direct sunlight for the trees to grow robustly and to provide abundant, healthy crops – ideally six to eight hours a day. Be aware of any larger trees – or trees that will potentially grow large in the future – that are adjacent to your orchard, either on your plot or your neighbor’s land. These trees may shade out your fruit trees, and compete with them for soil nutrients. However, fruit trees are also susceptible to damage from string winds, so you might want to consider planting trees to act as a windbreak, as long as they won’t shade out the fruit trees.

They also need well-drained soil. A slight slope can be particularly apt as it allows water to drain slowly and avoids the risk of soil erosion. If planting on flat land, make sure the soil is humus-rich by adding lots of organic material, and not too high in clay.

Choose Trees
The two primary things to consider when choosing fruit trees for your orchard are which are suited to your location, and what fruit you like to eat. However, most fruit trees will flourish in most situations given enough sunlight and a well-drained soil. It is worth bearing in mind that some fruit trees – such as Golden Delicious apples, Bartlett pears and most varieties of peach – self-pollinate, meaning you can have just a single specimen in the orchard and it will still set fruit. Others require at least two individual trees in order to cross-pollinate and set fruit. If neighbors have trees of the fruit you want to grow on their property, you may well get pollination that way, but having at least two on your plot is the best guarantee. For these species, plant the specimens next to each other to assist with pollination (and to make harvesting easier).

Soil
Preparing the soil before you plant your orchard is a very good investment to make. It is much harder to adjust the soil once the trees are in the ground. Add lost of organic material to the soil and water it in well. Not only will this help with drainage and nutrient supply, it should get the soil pH to around the desired level. Most fruit species prefer a soil pH of between 6.5 and 7. If your soil is still too alkaline, add some composted animal manure or compost with coffee ground in it, while if the soil is too acidic, consider adding some organic agricultural lime.

Spacing
Consider the space that your fruit trees will need when fully grown. You want them to be close to each other but not so close that their plan an orchard canopies intermingle, as this can affect growth and crop productivity. Individual species will requires distinct spacing, but as a general rule you want to allow a 10-foot circle around a dwarf fruit tree, and a 25-foot circle around a standard-sized tree. If possible orientate your trees north to south so they get maximum exposure to the sun.

Companions
Allowing sufficient space for your fruit trees also gives you room to plant companion plants around each tree in a guild that will benefit both the fruit tree and the companion plants. For instance, the tree can give shade to lower-lying legumes that fix nitrogen in the soil that the tree accesses. Different fruit species favor different companions, but an apple tree guild, for example, could contain dill and fennel that attract pollinating insects, as well artichokes, whose roots help keep the soil in good condition, and nasturtiums to repel pest insects. It is worth considering that most fruit tree species do not do well if surrounded by grass, as the grass competes with the tree roots for soil nutrients and moisture. Plant companions that suppress grass growth, such as leeks, garlic or daffodils. You can also mulch around the tree – although always leave a space around the trunk.

Cold Hardy Fruit Trees for Gardening in Zones 3-7

The hardiest fruit trees are Apples, Pears, and Plums which survive Zone 3 temperatures (-30 degrees to -40 degrees Fahrenheit). In Zone 4, many varieties of berries, Plums, Persimmons, Cherries, and Apricots do very well. In Zone 5 there are more options such as Peaches, Mulberries, and Paw paws. These zones receive temperatures as low as 20 or 30 degrees below. Fortunately I can grow more types of fruit in my gardening zone 6 and 7. Zone 6 receives temperatures of 0 degrees through -10 degrees F during the Winter while Zone 7 receives temperatures of 10 degrees through 0 degrees F.

Because I have listed below Fruits I can grow for my area, you may want to investigate each fruit for your area. For example the Paw paw fruit is adapted for Zones 5-9, so if you live in Zone 3 or 4, you may not be able to grow the Tree in a permanent location, but you may be able to grow Fruit trees in a large pot. Some of you in Rental homes, apartments, or Urban situations, can grow Fruit trees in containers. Last week I posted several pictures and list a exotic Fruit trees which can grow in large pots instead of in a permanent location. Go to Grow Veggies & Fruit trees in Containers for the details.

Apples are the most common Fruit trees I see growing in my community. Because Apples are one of the most hardy fruits, I highly recommend everyone in a colder climate to grow an Apple Orchard if you cannot grow any other Fruit trees.
 I did not want to focus on the most common Fruits, however. In this post I wanted to present a list of  unique or uncommon Cold hardy fruit trees which can be grown from Gardening Zones 3-7:

Chinese Jujube 
Ziziphus jujuba 

"Jujube grows throughout most of the southern half of North America. For best crops, the tree needs a long growing season and hot and dry weather during ripening. About the only parts of the United States where jujube can't grow are in the North (USDA Zones 5 and colder) and the Gulf Coast where summer rain and humidity prevent optimum fruiting...average winter minimum temperatures between -5° F (zone 6) and -15° F (zone 5) are the likely hardiness limits, trees have survived -25° F" (NGA.) From what I have seen, the Jujube fruit looks like a small apple, then once it has dried on the tree, it simulates a Date fruit.  They are absolutely sweet and crunchy.


Ice Cream Banana 
Musa acuminata × balbisiana 'Blue Java'
Ice Cream (Blue Java) Banana is a cold tolerant banana plant with texture and flavor similar to vanilla ice cream. This banana tree has beautiful large leaves and produces medium bunches of silvery blue bananas that are very delicious fresh or cooked. Mature banana tree reach 12 to 15 feet in height. The leaves are a silver-green color. The fruit peel appears blue-green in color. Many rate this banana the best tasting, which is fortunate considering it can withstand Zone 6 temperatures. Most gardeners recommend covering the entire plant in leaf material and mulch to "winterize" the plant. Even most Zone 6-7 gardeners wrap their banana tree with other protection like bubble wrap, blankets, and tarpaulin. In the photo below, a Musa basjoo banana tree is protected with straw and wire mesh to guard against cold temperatures.


Paw-Paw Tree
Asimina triloba
With huge leaves that look more at home in the jungle, the Paw Paw is actually an "Eastern U.S. native, hardy to -25° F! A forest understory tree quite happy in shade, it also tolerates full sun. The fruits, weighing up to a pound each, are rich, sweet, and custard-like, with hints of banana and vanilla. 15 to 30 feet tall. Plant at least two for pollination. Very Cold-Hardy. Rediscover this neglected American classic! Zones 4-9".


Hardy Chicago Fig  
Ficus carica 
 Also known as 'Bensonhurst Purple' whose origins are from Sicily, this tree can take sub-freezing temperatures, die back to the ground in the winter, and then re-sprout in the spring and bear Fall fruit on new growth. It is quite suitable for growing in a pot or a greenhouse. "The secret to winter survival is to keep it reasonably dry and above 10°F for the stem or -25°F for the roots. Of course, a fig grown in this manner will take on a shrub-like form rather than a standard tree-form. If a tree shape is desired it would be best to pot it up and sink the container into the ground, then dig it up in late Fall and store it in a garage; 40°F would be ideal, but above 25°F is sufficient  Alternatively, the tree could be taken inside and treated as a house plant" (ManchesterGardenClub).
Other varieties of Figs, such as Celeste and Brown Turkey fig trees are also cold tolerant, withstanding Zone 5 temperatures. Remember to wrap Fig trees the first few Winters with cloth and plastic and/or heavily mulching with leaves.


Cold Hardy Kiwi
Actinidia arguta
The hardy kiwifruit is native to northeastern Asia, tolerating temperatures as low as -25°F. In the eastern United States, the commercial kiwifruit grows only as far north as Maryland, and they are sensitive to late spring frosts. The small fruit is smooth skinned unlike commercial kiwis with fuzzy skin. "Purchase at least one male plant for every nine female plants to ensure pollination and fruit set. Avoid planting in frost pockets. Sites with northern exposure are good because they delay early growth in spring, which can be damaged by late frosts. Construct a trellis system or otherwise support vines...Kiwifruit will not reach maturity and flower until about their fifth year." (Cornell University).



Che 
Cudrania Tricuspidata
The Che is related to the Mulberry, but the Che fruit looks identical to the Lychee fruit, resembling a brain. The Che is Native to many parts of eastern Asia from the Shantung and Kiangson Provinces of China to the Nepalese sub-Himalayas. It became naturalized in Japan many years ago, and later was introduced into England and other parts of Europe around 1872, and in 1930 was introduced to the U.S.
"The Che requires minimal care and has a tolerance of drought and poor soils similar to that of the related mulberry. It can be grown in most parts of California and other parts of the country, withstanding temperatures of -20° F...They perform best in a warm, well-drained soil, ideally a deep loam" (California Rare Fruit Growers).


Passion Fruit (Maypop)
Passiflora incarnata
This hardy perennial plant thrives in climates of -25 degrees F. The plant can be grown in Zones 5-11.
Ideal for containers in any climate and very easy in the garden, Maypop reaches 8 to 12 feet long. It will die back completely to the ground in winter and not reappear until late spring. The fruit appears egg-shaped and the flavor will remind you of Passionfruit, while the aroma is musky. The leaves are 5 to 6 inches wide and up to 8 inches long.



Gooseberry
Ribes uva-crispa
"Indigenous to many parts of Europe and western Asia, growing naturally in alpine thickets and rocky woods in the lower country, from France eastward, well into the Himalayas and peninsular India" (Gooseberry). Gooseberries grow best in summer humid, cool regions with great winter chilling. Gooseberries are deciduous shrubs, fast growing, and reaches 3 feet tall and 6 feet wide. Gooseberries look like veiny Grapes, usually red or green in color.



Quince
Cydonia oblonga
"The fruit is much more common through South America, Europe and the Middle East than it is in North America. You can grow quince between zones 4 and 9, as they can tolerate freezing temperatures during the winters as long as the flowers aren’t hit with a late hard frost. Quince fruit is very tart and sour even when mature..." (Backyard Gardening). Since quince have naturally shallow roots, they may survive in large containers, and may also grow like a bush rather than a tree. They take three years to begin producing fruit.

Goumi
Elaeagnus multiflora
Native to the Far East, this shrub reaches 4 to 6 foot tall. Self-fertile, not bothered by pests or diseases, tolerates a wide range of soils, and fixes nitrogen in the soil. Goumi plants have silvery leaves underside. They begin producing fruit in two to three years, with fragrant creamy-white flowers in May followed by tasty and aromatic red fruits. Looks like a Goji Berry fruit, but with hints of cherries, apples and black currant flavor. Grows well in USDA gardening Zones 4-9.


Currants
Ribes
"Red, pink and white currants belong to three European species (Ribes rubrum, R. petraeum, R. sativum). Black currants are related to European (R. nigrum) and Asian (R. ussuriense) species.
Other Related Species are the Gooseberry (Ribes grossularia, R. hirtellum), Buffalo Currant (R. aureum), Jostaberry (R. nigrum X hirtellum). Currants grow best in summer humid, cool regions with great winter chilling. They are best adapted to USDA Hardiness Zones 3 through 5...Bushes grown from seed bear when two or three years old" (CRFG).


Cranberry
Vaccinium macrocarpon
Cranberries are low, creeping shrubs or vines up to 7 ft long and 2 to 8 in in height. They "have slender, wiry stems that are not thickly woody and have small evergreen leaves. The flowers are dark pink, with very distinct reflexed petals, leaving the style and stamens fully exposed and pointing forward. They are pollinated by bees" (Cranberry). The berry is initially white, turning into a deep red when fully ripe. Has an acidic taste that can overwhelm its sweetness. Cranberries require an adequate fresh water supply, and a growing season that extends from April to November. They "grow on low-lying vines in beds layered with sand, peat, gravel and clay. These beds are commonly known as bogs or marshes and were originally created by glacial deposits...Cranberries are grown through the northern part of the United States. The major production areas are New Jersey, Massachusetts, Oregon, Washington, Wisconsin and the Canadian provinces of British Columbia and Quebec. Other regions grow cranberries as well, to varying extent, and these include Delaware, Maine, Michigan" (CCCGA).


Elderberry
Sambucus canadensis
The American elderberry is a common plant that takes little effort to forage. It is not a rare plant, in fact I consider this plant to be a weed, considering I have identified them on the sides of roads, in the woods, and in yards. Elderberries grow all over North America, so you will not have problems finding/growing this plant. Elderberries fruit best when you plant at least two different varieties. They start producing the first year of transplant but will take 2 to 3 years to produce fruit from seed. When I have harvested elderberries, I found them to be sour in taste; but if that is your thing, there are several varieties of the American elderberry that are good fruit producers, like the Adams, Black beauty, Black Lace, Johns, Nova, Variegated, and York (NGA). Some would say the Poke plant bears fruit similar to the Elderberry, as well as the plant Devil's Walking Stick.


Mulberry
Morus
"Morus alba, white mulberry, and M. nigra, black mulberry, are native to China. Morus rubra, red mulberry, is a North American species, ranging from the mid-Atlantic to Florida and west to Nebraska and Texas. Morus nigra is cultivated throughout Europe for its large, sweet-tart fruit. Morus alba is the hardiest, surviving –25F. and colder, though its fruit quality varies greatly.
The genus name Morus is derived from the Latin ‘mora,’ which means ‘delay,’ and refers to the late leafing habit of the mulberry...This delay ensures that its fruit buds appear well after danger of frost has passed...Mulberries are 30- to 50-foot, fast growing, long-lived deciduous trees with alternate, simple, lobed to undivided leaves. Leaves on one tree can be lobed and [un-lobed]. Though both monoecious (male and female flowers on one plant) and dioecious (male and female flowers on separate plants), many trees are self-pollinating. Trees are also known to change sex. The tree flowers inconspicuously in late spring on the current season’s wood and on spurs of old wood...Fruits, which ripen in midsummer, are small fleshy drupes, resembling a tightly beaded blackberry. Fruit color ranges from white to lavender to red and purplish-black. Some mulberries are seeded, though I have known over two dozen trees and never met a seed. The flavor is mild and very sweet, but M. alba is said to lack the perfect blend of sweetness and tartness of M. nigra. I have tasted only M. alba and love it. If I need the tartness for any reason, I mix in some under-ripe fruits. As I noted before, beware: The dark fruit stains badly" (MOFGA).


Chokeberry 
Aronia melanocarpa
This shrub can be planted in Zones 3-8., and usually grows to 3-6' tall and wide, though it can be up to 10' in width.You can plant the black chokeberry in either full sun or partial shade...Black chokeberry has dark green leaves that are 1-3" long and lanceolate or elliptical in shape. In the fall they change to reddish hues, similar looking to the Blueberry bush. "The white flowers appear during springtime and come in clusters called corymbs. The fruit produced is a small black pome that has tannins which pack pucker power" (Myers).

Jostaberry
Ribes × nidigrolaria
"Jostaberries are hybrids of black currant and the American gooseberry, R. hirtellum, produced in Germany, 1930s-50s... The bush is very tall, thorn-less, tends not to branch and requires the space of 2 currant bushes. The foliage is glossy, larger than gooseberry, lobed, scentless and resists mildew. It survives full sunlight but requires much winter chilling. The lateral buds usually shed, leaving blind branches. Purple or brownish-red fruit are borne on lax, few-berried strigs. They are the size of small gooseberry and lacking in flavor, suitable only for experimentation. Buffalo currant produces comparable fruit more abundantly in less space and is recommended instead" (CRFG).

Saskatoon (Serviceberry)
Amelanchier alnifolia
"Native to North America from Alaska across most of western Canada and in the western and north-central United States. Historically, it was also called "pigeon berry". It grows from sea level in the north of the range, up to 2,600 m (8,530 ft) elevation in California and 3,400 m (11,200 ft) in the Rocky Mountains...Saskatoons are adaptable to most soil types with exception of poorly drained or heavy clay soils lacking organic matter. Shallow soils should be avoided, especially if the water table is high or erratic. Winter hardiness is exceptional, but frost can damage blooms as late as May. Large amounts of sunshine are needed for fruit ripening. With a sweet, nutty taste, the fruits have long been eaten by Canada's aboriginal people, fresh or dried" (Amelanchier alnifolia).

Sea Buckthorn (Seaberry)
Hippophae rhamnoides
 "The plant is a thorny shrub that can survive the harshest weather conditions.  As it turns out the Prairies are an ideal habitat for Sea Buckthorn...Sea Buckthorn has an extensive rooting system and a nitrogen fixation property. Seabuckthorn has been planted to rejuvenate marginal land and soil conservation" (Solberry Seabuckthorn). Sea Buckthorn is an "incredibly important natural resources in the mountainous regions of China and Russia, and the Canadian prairies. The plant will grow naturally in both sandy, and clay soils. In fact the plant will thrive in nearly any soil type, but it is extremely intolerant of shady planting sites. The shrubs themselves are also very cold-hardy. The plants can withstand winter temperatures of up to -40 degrees Celsius (-43 degress F). It is also commonly found growing at high altitudes of 4000 to 14000 feet" (Sea buckthorn insider).


Russian Pomegrante
Punica granatum
Pomegranates prefer semi-arid and mild temperate climate with cool winters/hot summers. It can grow in the sunniest part of the yard with well drained sandy soil as well as rock gravel. The plants can take considerable drought but must be irrigated for fruit production. Pomegranates develop into round bushy small trees 6 to 8 feet tall except dwarf varieties ranging from 3 to 7 feet. In warmer climates with longer growing seasons will have larger bushes (up to 15 feet tall)" (Edible Landscaping). Pomegranates are self pollinating, but it's encouraged that another pomegranate tree is present for pollination. It will take 2-3 years to start bearing fruit. The Russian Pomegranate survives USDA gardening Zones 6-10.

Lingonberry (Cowberry)
Vaccinium vitis-idaea
This shrub is native to the Arctic tundra throughout the Northern Hemisphere from Eurasia to North America. It reaches 12 to 18 inches in height. "It is extremely hardy, tolerating temperatures as low as −40 °C (−40 °F) or lower, but grows poorly where summers are hot. It prefers some shade (as from a forest canopy) and constantly moist, acidic soil. Nutrient-poor soils are tolerated but not alkaline soils" (Vaccinium vitis-idaea). Because it is so cold tolerant, the berry does not produce reliably in warmer climates like Zone 9-11. "Lingonberries are self-pollinating, but cross-pollination will produce larger fruits that ripen earlier...Bumblebees are the best natural lingonberry pollinators. Plants need two to three years to begin bearing good crops" (NGA).


The Medlar
Mespilus germanica
"Indigenous to southwest Asia and also southeastern Europe, especially the Black Sea coasts of Bulgaria and of modern Turkey. It may have been cultivated for as long as 3000 years...Requires warm summers and mild winters and prefers sunny, dry locations and slightly acidic soil. Under ideal circumstances, the deciduous plant grows up to 8 metres (26 ft) tall" (Mespilus germanica). Generally has a lifespan of 30-50 years, and is shorter and more shrub-like than tree-like.

Hawthorn berry
Crataegus 
"Native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name "hawthorn" was originally applied to the species native to northern Europe, especially the common hawthorn C. monogyna, and the unmodified name is often so used in Britain and Ireland. The name is now also applied to the entire genus and to the related Asian genus Rhaphiolepis...the Common Hawthorn, C. monogyna, are edible but the [flavor] has been compared to over-ripe apples...the fruits of the species Crataegus pinnatifida (Chinese hawthorn) are tart, bright red, and resemble small crabapple fruits." (Crataegus).


Silver buffaloberry
Shepherdia argentea
This thorny, deciduous shrub grows up to 20 feet tall. It is native to northern and western North America. The plant grows in USDA Zone 2, so it tolerates cold winters, drought and also tolerates infertile soil.

Thimbleberry 
Rubus parviflorus
 "Native to western and northern North America, and the Great Lakes region...Thimbleberry fruits are larger, flatter, and softer than raspberries" (Rubus parviflorus). The plant reaches up to 10 feet tall and blooms white petals. The leads grow to 10 inches long, fuzzy, deciduous maple-like shape. The plant needs Full sun to shade with moist to dry, humus rich soil. "Thimbleberries do not grow well on sandy or gravelly soils, but in the Northwest, a small percentage grow in wet soils" (Rainy side Gardeners).




This list of Fruit bushes and trees are a fraction of what is possible to grow in cold climates. As plant species continue to cross-pollinate, there will be that much more fruit to grow. Of course there are many more varieties of Berries and Currants that grow in cold climates, For example, Sourberry (Rhus trilobata), Wax Currant (ribes cereum), American silverberry (elaeagnus commutata), Creeping barberry (mahonia repen), honeyberry, boysenberry, huckleberry, dewberry, tayberry, youngberry, and Marionberry.

Do not limit yourself to fruit bushes and common cold hardy fruits. From GardenWeb.com, one gardener said he was growing a Papaya tree in Zone 5/6a, which he grows in a container outside during the Summer, and he brings the Papaya tree inside during the Winter next to a South facing window. I was very shocked that he even posted pictures of his Papaya harvest. Click the link for details and pictures of the Papaya growing in a cold climate: Fruiting Papaya in Zone 5/6.

Northern gardeners grow sub tropical fruits like Limes, Lemons, Mandarin oranges, as well as tropical pineapple and Mangoes in containers. When growing Fruit plants in containers, you will be able to relocate the fruit inside your home or in a greenhouse where it will be protected over winter. I have a post on Growing Fruit in Containers: Grow Veggies & Fruit trees in Containers (Limited Space & Urban gardening.

If Papaya can be grown in a container or in a greenhouse, I believe Feijoa, Surinam Cherry, Pineapple Guava, Cold Hardy Avocado, Cavendish Banana, Dragon fruit, and Loquats can be grown in cold to mild climates such as Zone 4-7. Growing many of the varieties of Tropical fruit trees can be achieved through Underground Greenhouses, growing in containers indoors, compost heating/Hugelkultur methods, artificial lighting/heating.