Thiessen is one of the most popular Saskatoon or Juneberry varieties, with a particularly good sharp tangy flavour.
The tree is vigorous and the berry-like fruits are amongst the largest of their kind.
The fruits ripen progressively over a long period, starting in early summer.
Thiessen was discovered as a wild seedling in Sasketchewan, Canada, in 1906, making it one of the oldest and most widely-grown Saskatoon varieties. It is known to grow productively for more than 50 years.
Thiessen is an early-flowering Saskatoon, and like all Saskatoons is very susceptible to frost damage, so best planted in a sheltered frost-free area.
Thiessen grows with a more spreading habit than other Saskatoons, and if planting several bushes, allow up to 3m between each one.They should reach a mature height of about 2m-3m or so in the UK - in Canada Thiessen reaches 4m-5m. After a few years it becomes a large sprawling bush.
Do not add fertiliser at the time of planting, but water well, and keep the young bush regularly watered (but not drowing) during the spring. Water should be applied to the base of the stem and the root area, try to avoid letting water splash on to the leaves. Keep weeds and grass well away from the base of the plant.
No pruning is usually required for the first 5 years. After that, prune out some of the older branches each spring, since fruiting is best on younger shoots.
Sasksatoons belong to the species Amelanchier alnifolia and originate from the western regions of North America, and was well-known to native Americans. Today Saskatoons are grown commercially in central Canada - including around the city of Saskatoon in the province of Sasketchewan. In the USA they are generally known as Juneberries.
Saskatoons are often compared to blueberries, since the fruits look similar. However Saskatoons are not berries, in fact they are more closely related to crab-apples. They are also much easier to grow than blueberries. The fruits are quite similar in taste and appearance to blueberries though, and can be used for similar purposes. Saskatoons can be eaten fresh, or made into preserves, dried, juiced, or used in pies and crumbles. Saskatoons are highly regarded for their antioxidant and nutritional properties, and are often considered to be a "super food". Saskatoons are a common ingredient in the native American "pemmican" trail food.
The bush-like trees are very cold-hardy and will grow in most well-drained soils - but avoid clay or water-logged soils. They prefer neutral or slightly acidic conditions, but will tolerate slightly alkaline soils. The flowers, which appear during May, are susceptible to frost damage, so avoid planting in areas prone to late frosts. Saskatoons are used to the intense sunshine of the western states of North America, so make sure you plant them in full sun.
In northern European conditions Saskatoons are likely to grow to about 2m - 3m tall, with a similar spread, and will start bearing after 3-4 years. We produce our Saskatoon plants from cuttings or by grafting on to Sorbus rootstocks.
Fruit production on a mature bush is likely to be 2kg-4kg.
If you don't like pruning then it is useful to know that routine pruning is not essential with Saskatoons. However pruning back in early spring is beneficial to encourage more shoots - because the best quality fruit is produced on younger wood. It is also a good idea to cut out the thickest shoots after 5 years or so, to make way for younger growth.
Saskatoons are best left to grow in their natural form, which is an upright bush. Over time multiple stems may develop. An alternative approach is to allow the plant to grow in a loose fan shape, supported on a south-facing wall.
The fruits follow quickly after the blossom - hence the common name 'Juneberry' although in northern Europe the fruits are more likely to ripen in July. Like cherries, they are attractive to birds, so it helps to net the fruit.
All Saskatoons are reliably self-fertile but will crop more heavily if several bushes of different varieties are planted together.
This variety description was researched and written by Orange Pippin staff. Last checked: 2024.