Pollination
  self-fertile
pH
  6.0 to 7.0 is preferred, 4.5 to 8.0 is acceptable.
Yield
  stems between the ages of 2-4 years old are the most productive.
Tolerant
  partial shade (disease may become an issue for some species)
Juneberries are also called saskatoon or serviceberries.

Native Range and Climate

The western juneberry (Amelanchier alnifolia) is the most common juneberry species and is one of the few native to the western half of North America.  Their range extends from western Minnesota to northwestern California and all the way up to central Alaska.  They can also be found in scattered parts of the mountain ranges further south.

The climates they generally reside in are warm continental (Dfb, Dsb), warm mediterranean (Csb), and subarctic (Dfc).  While their range often receives an annual rainfall of less than 20 inches (possibly down to 11 inches), it does not extend too far into the semi-arid climate (BSk) and even makes a point to avoid it.  A. alnifolia does not extend too far into hot summer climates as well (Dfa).

There are many other juneberry species, most of which are native to the wet and humid eastern half of the United States and southeastern Canada.  Amelanchier arborea, canadensis, laevis, and spicata are commonly found in the north and the south, while A. humilis, interior, stolonifera, sanguinea, and nantucketensis are found primarily in the north.


Flavor

Juneberries have a low acid content are said to range between insipid to quite good, depending on the variety, but they are always considered to be inferior to more popular culinary berries.  This, of course, could change with the introduction of new varieties.  The flavor is often mentioned by writers, nurseries, and studies to be somewhat like a blueberry, but home-growers almost always disagree.  They generally claim juneberries taste like sweet almonds or a combination of sweet almond and apple, but I have seen a few add blueberry or cherry to the mix.  Considering most varieties come from A. alnifolia, it's possible some of these other species are more or less likely to contain more berry-like flavors.  Additionally, a few have said or implied that they become more palatable when cooked.  While juneberries appear to have great potential, the sample size of opinions, at this time, is fairly small, since only a few have developed a great interest in the fruit.

In my limited experience, the flavor was quite mild, and they did not taste like almond, apple, or blueberry to me.  The seeds did make them somewhat nutty, and the flesh was often berry-like, occasionally reminiscent of sweet cherry.  They were fairly good when dried, but I did not try them cooked.  Rain, at some level, seemed to water down their already light flavor, and those that weren't mostly purple in color had practically no flavor.  I was only able to sample from a few small bushes, and I do not know their exact species, but some of them were seedlings of species native to the east or hybrids between them and alnifolia.


Disease

Since A. alnifolia is native to a drier climate than most other juneberry species, they tend to be more susceptible to disease.  Based on one year at Edmonton, Alberta and two years at Hudson Bay, Saskatchewan, nearly 100% of the leaves were infected with entomosporium spot, but the average percentage of the leaf area affected on the most vulnerable varieties tested generally resided between 3-7%.[1] It does not mention if the infection was severe enough to cause early defoliation.  More importantly, based on one year at Hudson Bay and Moonlake, Saskatchewan, nearly 100% of the fruit were also affected.[1] Severity was implied to be very high at Moonlake, but the damage was likely enough to ruin commercial crops at both locations.

In Alberta, Canada, entomosporium spot began being a problem in 1990, and by 1994, the disease was severe enough to ruin over 80% of the crop at most orchards, without the use of fungicides.[2] These observations were made within their native range near cities that receive an average annual rainfall around 17 to 18 inches (most of which falls during spring and summer).  The region is also further up north, which means daytime lasts for a greater duration during the summer.  This would help the leaves dry quicker, creating less favorable conditions for disease.

I cannot say if the infection will be severe enough to ruin the crop for home-growers with low density alnifolia plantings, since they are likely more forgiving, but, based on a small sample size, I have only heard complaints about spotting (and mildew) from those growing western juneberries outside of their native range.  Overall, we can assume A. alnifolia is not suitable in wetter climates without the use of fungicides.  Amelanchier species native to the east may be more desirable, but with the possible exception of "Autumn Brilliance", none are really known for their superior fruit quality, since they are only sold for ornamental purposes.  However, rust can ruin the entire crop of at least some eastern species, especially when planted in a more shaded location.

Juneberries can also suffer from fireblight, but I have only heard of one complaint from home-growers.  Some have even made a point to say that they have never seen blight on their juneberries, including one who has lost apple trees due to the disease, but I am not sure if these home-growers were referring to eastern or western Amelanchier species, although they were located in the east.


Toxicity

Like many other species in the Rosaceae family, juneberries contain cyanogenic glucosides, such as prunasin and amygdalin, in the leaves, branches, and seeds.  The fruit is the only part that is generally considered edible.  These substances convert into hydrogen cyanide in the body, which can be highly toxic in fairly small amounts.  When it comes to juneberries, avoiding the consumption of the seeds is not practical, nor is it considered, implying the amount of cyanogenic glucosides present is small enough to tolerate.  However, it's still nice to know, how much is too much? I have only found one study that made it somewhat clear.

Six plants consisting of 5 different varieties grown in one of three different regions were tested to determine the maximum amount of hydrogen cyanide (HCN) they could produce.  Smoky was the only variety tested at two different locations, and at both locations, it had a much higher potential HCN than the other varieties (4.4 mg/kg in the red stage and 9.4 in the purple stage at Manitoba, and 8.19 mg/kg in the red stage and 7.59 in the purple stage at Alberta), with the exception of Theissen (8.15 mg/kg in the purple stage - the only stage tested).[3] Honeywood (4.24 mg/kg in the red stage and 3.08 in the purple stage), Northline (5.94 mg/kg in the red stage and 3.51 in the purple stage), and Martin (slightly above 3 mg/kg in the red, red-purple, and the purple stage) were the other varieties tested.  Most, but not all, had a much lower potential HCN amount in (what I assume to be the late part of) the green stage.[3]

For comparison, sweet almonds can produce roughly 2x to 10x the amount of hydrogen cyanide (16.2 to 32.4 mg/kg)[4] as Smoky and Theissen juneberries, although this too is based on a small sample size.  Bitter almonds (918 to 1215 mg/kg) and apricot kernels (540 to 1193.4 mg/kg) can produce significantly more hydrogen cyanide and should be avoided entirely.[4]

The study mentions the World Health Organization's 2004 "accepted cyanide toxicity level" was 1 mg/kg body weight.[3] Not only do I not see that in their source, but their choice of words severely underplays how dangerous it can be to consume that much hydrogen cyanide.  Their source, however, does imply the LD50 for humans is around 1.4 mg/kg body weight (bw) and the lowest reported lethal dose was 0.54 mg/kg bw.  In other studies, the acute oral lethal dose of HCN for humans is often cited to be 0.5-3.5 mg/kg bw.[5]

While using the highest value of potential HCN from the study (9.4 mg/kg) along with the acute oral lethal dose of 0.5 mg/kg bw, and assuming a 100% hydrolysis of the glucosides within the body, a 56 pound (25kg) child should not consume anywhere near 2.9 pounds (1.33kg) worth of juneberries.  This would amount to 8.2 pounds (3.72kg) for a 154 pound (70kg) adult.

Due to the uncertainty of the type of damage chronic intake may cause, various organizations have established a Tolerable Daily Intake (TDI) of cyanide significantly lower than the minimum acute oral lethal dose of 0.5 mg/kg bw.  The Committee on Toxicity states that one should not consume more than 0.042mg/kg bw of cyanide within one hour or 0.083 mg/kg bw per day, while the Counsel of Europe and WHO established a TDI of 0.02 mg/kg bw or lower.[6]

Using the TDI of 0.02 mg/kg bw along with the highest potential HCN value from the study (9.4 mg/kg) and the average value for all six results in the purple stage (5.79 mg/kg) for a 56 pound (25kg) child and a 154 pound (70kg) adult, we get a maximum limit of 53.2g (0.117 pounds) to 86.4g (0.19 pounds) for the child and 149g ( 0.328 pounds) to 242g ( 0.533 pounds) for the adult per day.  For comparison, a 2-1/8" diameter plum is said to be around 66g.



Read More

Western Juneberry
Amelanchier alnifolia

Bluff

Zone
:
2
Fruit Size
:
~0.8g/berry
Afflictions
:
Somewhat resistant to mildew?
Susceptible to entomosporium spot.

Buffalo

Zone
:
2
Fruit Size
:
~0.95g/berry
Afflictions
:
Susceptible to entomosporium spot.

Forestburg

Zone
:
2
Fruit Size
:
~1.14g/berry
Afflictions
:
Susceptible to entomosporium spot.

Honeywood

Discovered in Parkside, Saskatchewan (1955).
Zone
:
2
Blooms
💮:
  .......   :   0.5 to 1 week after most other A.  alnifolia
Ripens
🍏:
  .......   :   precocious
ripens somewhat evenly
somewhat biennial

Tree Size
:
15ft H x 12ft W
Fruit Size
:
~1.07g/berry, ~12.3mm
Yield
:
moderate to highly productive
Afflictions
:
Somewhat resistant to mildew.  
Somewhat susceptible to entomosporium spot.
low to moderate suckering

JB30

Originated in Langham, Saskatchewan, introduced in 1991.
Alias
:
Quaker
Zone
:
2

Flavor
:
may have some acidity
Tree Size
:
12ft H
Fruit Size
:
~1.35g/berry, ~13mm
Yield
:
moderately productive
Afflictions
:
At least somewhat susceptible to entomosporium spot.
low suckering

Lee 3

Pembina x ?  Originated near Barrhead, Alberta. Introduced in 1994.
Zone
:
2
Tree Size
:
6-9ft H
Fruit Size
:
up to 16mm

Martin

Thiessen x ?  Originated in Langham, Saskatchewan. Introduced in 1990.
Zone
:
2
Ripens
🍏:
  .......   :   ripens somewhat evenly

Tree Size
:
10ft H
Fruit Size
:
~1.66g/berry, ~14mm
Yield
:
moderately productive
Afflictions
:
Somewhat susceptible to entomosporium spot.
low to moderate suckering

Nelson

Originated near Bradwell, Saskatchewan. Introduced in 1992.
Zone
:
2
Ripens
🍏:
  .......   :   ripens unevenly

Tree Size
:
5ft H
Fruit Size
:
~1.03g/berry, ~12mm
Yield
:
low to moderately productive
Afflictions
:
May have some resistance to saskatoon-juniper rust, but I doubt it's suitable for the south.  
Somewhat susceptible to entomosporium spot.
The water content of Nelson may reside around 75%, making it 2-5% drier than most other juneberry varieties, and while the acid content is still quite low, Nelson was one of the most acidic varieties available, giving it a pH of 3.65.  Most varieties have a pH around 4.  Martin (3.71) and PAR90 (3.70) had the second lowest pH values.  Nelson also had the second highest mean brix value (18.8) during a 3 year study in Saskatchewan.

low to moderate suckering

Northline

Fruit Size
:
~1.06g/berry
Afflictions
:
Susceptible to entomosporium spot.

PAR90

Fruit Size
:
~1.59g/berry
Afflictions
:
The fruit are Susceptible to entomosporium spot but the leaves are somewhat resistant.

Pearson II

Zone
:
2
Fruit Size
:
~1.11g/berry
Afflictions
:
Susceptible to entomosporium spot.

Pembina

Originated near Barrhead, Alberta. Introduced in 1956.
Zone
:
2
Ripens
🍏:
  .......   :   ripens somewhat evenly

Tree Size
:
15ft H x 15ft W
Fruit Size
:
~0.85g/berry, ~11.4mm
Yield
:
contradicting results on productivity?
Afflictions
:
Somewhat susceptible to entomosporium spot.  Susceptible to cracking.
The water content of Pembina may be as low as 71-72%.  Most fruit reside between 80-90%, and most other juneberry varieties reside around 77-80%.

Pembina had the highest mean brix value (20.1) during a 3 year study in Saskatchewan (most were between 14 and 17).  It may also have a sorbitol content higher than the average variety, based on another study where its sorbitol content was higher than Smoky in-spite of having a lower overall sugar content.

low suckering

Smoky

Originated near Beaverlodge, Alberta. Introduced in 1956.
Alias
:
Smoky
Zone
:
2
Ripens
🍏:
  .......   :   somewhat of a biennial bearer

Tree Size
:
15ft H x 18ft W
Fruit Size
:
~1.09g/berry, ~12.3 to 14mm
Yield
:
highly productive
Afflictions
:
Somewhat susceptible to entomosporium spot.
Smoky is (or was) the most commercially cultivated variety in Canada.

Smoky may have a higher sorbitol content than normal (3.37g/100g in a 1 year study).  This is compared to Honeywood (2.25g/100g), Martin (2.41g/100g), Pembina (1.84g/100g - some other data on Pembina seemed highly erroneous), and 3 unnamed varieties (1.8 to 2.49g/100g).  However, in another study, Smoky's sorbitol level was more in line with, but slightly higher than, some of the other varieties, such as Martin and Theissen (Pembina managed to be higher than Smoky).

moderate to high suckering

Thiessen

Originated west of Hepburn, Saskatchewan. Discovered in 1906 but introduced in 1976. ***
Zone
:
2
Ripens
🍏:
  .......   :   ripens unevenly

Tree Size
:
15ft H x 18ft W
Fruit Size
:
~1.62g/berry, ~14 to 17mm
Yield
:
moderately productive
Afflictions
:
Somewhat resistant to mildew?
Susceptible to entomosporium spot.  Susceptible to Cytospora Canker?
Thiessen is (or was) the second most commercially cultivated variety in Canada.

low to moderate suckering

Thiessen RS

Thiessen RS is said to be similar to Thiessen, but it suckers less.

Hybrid Juneberry
Amelanchier hybrid

Autumn Brilliance

A. arborea x A. laevis.  Developed in Urbana, Illinois. PP5717 (1986).
Tree Size
:
24ft H
Fruit Size
:
6 to 8mm
Afflictions
:
Somewhat resistant to saskatoon-juniper rust? (contradicting reports)
highly ornamental fall colors

Parkhill

A. stolonifera x A. alnifolia.  introduced in Bismark, North Dakota (1974).
Zone
:
3
Tree Size
:
4.5ft H x 8ft W
Fruit Size
:
~0.97g/berry, ~11.6mm
Yield
:
moderately productive
Afflictions
:
Somewhat resistant to entomosporium spot.  
Susceptible to mildew.  
Somewhat susceptible to saskatoon-juniper rust?
moderate to high suckering

Regent

A. stolonifera x A. alnifolia.  Originated near Regent, North Dakota. Introduced in 1977?
Zone
:
3
Ripens
🍏:
  .......   :   precocious

Flavor
:
bland
Tree Size
:
6ft H x 6ft W
Fruit Size
:
13mm
Afflictions
:
Resistant to entomosporium spot.  
At least somewhat susceptible to saskatoon-juniper rust and fireblight.
ornamental fall colors

Success

A. stolonifera x A. alnifolia.  Originated in the Appalachian mountains of Pennsylvania. Introduced in 1878.
Zone
:
3
Tree Size
:
8ft H x 6ft W
Fruit Size
:
~0.79g/berry, ~11mm
Yield
:
lightly productive
Afflictions
:
Resistant to entomosporium spot.  
Susceptible to mildew.  
Somewhat susceptible to saskatoon-juniper rust?
low to moderate suckering / ornamental fall colors