saskatoon plants

Saskatoon berry and serviceberry plants: choosing a cultivar for fruit

Serviceberries belong to the genus Amelanchier in the rose family, alongside apples, pears, quinces and hawthorns. Their blue-purple fruit resembles a berry, but botanically it is a small pome constructed on the same principle as a miniature apple.

The commonly cultivated species produce edible fruit, but they are not equally valuable as fruit plants. Some serviceberries have been selected mainly for their spring blossom, habit or autumn colour, while cultivars derived primarily from Amelanchier alnifolia, known as Saskatoon berries in Canada, have been selected for productivity, fruit size and eating quality.

Saskatoon berry plants are exceptionally winter hardy and their fruit does not require an intensely hot summer to ripen. Successful cropping depends more on cultivar quality, sunlight, protection of the blossom from late frost, adequate moisture while the fruit develops, renewal of productive young stems and protection from birds.

Saskatoon berry or ornamental serviceberry?

Can one Saskatoon berry plant produce fruit?

Fruiting Saskatoon cultivars are generally self-fertile, or more precisely capable of setting fruit with their own pollen. A single plant can therefore produce without a second cultivar being essential.

The flowers are visited by bees, bumblebees and other pollinating insects. A second cultivar flowering at the same time may improve fruit set and cropping regularity, particularly when flowering weather is less favourable.

It is therefore inaccurate to state either that two plants are always required or that a second cultivar provides no benefit. One self-fertile cultivar is normally sufficient for a small garden, while two distinct cultivars can be useful where a heavier crop is desired.

Flowering occurs early in spring, often as the leaves are beginning to unfold. Cold, rainy or windy weather may reduce insect activity, while frost affecting open flowers can remove part or all of the crop despite the excellent winter hardiness of the shrub itself.

Winter hardiness and blossom frost are different issues

Saskatoon berries are among the most winter-hardy fruiting shrubs. The cold tolerance of dormant wood does not mean that flowers, young leaves and fresh shoots tolerate the same temperatures.

A spring frost may blacken open flowers, scorch young foliage or cause newly formed fruit to drop. The plant normally survives without difficulty, but the harvest for that season may be reduced.

The risk depends strongly on the local microclimate. A shrub planted in a hollow, at the bottom of a slope or behind an obstacle that traps cold air may suffer more damage than a plant only a few metres higher.

In cool regions, a very warm wall is not automatically the safest position. A sunny, slightly elevated site with good air movement is often preferable to an enclosed position that encourages the buds to open prematurely.

Useful characteristics when comparing Saskatoon cultivars

Seedling or named clonal cultivar?

A seed-grown plant is not a copy of the plant that produced the seed. Vigour, habit, fruit size, flavour, firmness and ripening period may all vary between seedlings.

Seedling populations can be useful for a wildlife hedge, a breeding project or fruit production where uniformity is unimportant. They are less suitable when the characteristics of a recognised cultivar are required.

Fruiting cultivars are propagated by cuttings, layering, division of suckers or tissue culture so that their genetic identity is preserved.

These plants normally grow on their own roots, meaning that suckers arising from the root system usually belong to the same cultivar.

There is no standardised range of dwarfing serviceberry rootstocks comparable with that available for apples. Species, cultivar and training method have a greater influence on final dimensions than the search for a particular rootstock.

Where should a Saskatoon berry be planted?

Serviceberries tolerate partial shade and can grow at the edge of woodland, but fruit production is normally better in full sun.

Strong light encourages flower formation, sugar accumulation, fruit colour and the renewal of productive young wood.

In northern and western Europe, choose a position receiving direct sunlight for most of the day. Light shade late in the afternoon is acceptable, but planting beneath the crown of mature trees often produces more foliage than fruit.

The shrub should remain accessible. Birds begin watching the crop before full maturity, and a plant that has become excessively tall or mixed into a dense hedge is difficult to net and harvest.

Allow for the mature dimensions of the cultivar. Some Saskatoon berries remain close to two metres, while others may reach three to five metres and spread progressively through suckers.

Which soil suits Saskatoon berry plants?

Serviceberries prefer deep, fertile soil that retains moisture but drains correctly. Loamy or clay-loam ground with a useful water reserve provides favourable conditions for growth and fruit development.

Unlike blueberries, serviceberries are not acid-loving heathland plants and do not require strongly acidic soil.

Many species tolerate a relatively broad pH range. Slightly acidic to neutral soil is generally ideal, while moderately calcareous ground can also be suitable when it remains deep and sufficiently moist.

The least favourable conditions are permanently waterlogged ground and extremely sandy, poor and drought-prone soil. Consistent moisture is useful, but water should not remain continuously around the root collar and root system.

In heavy ground, cultivate only once the soil has drained sufficiently. Working wet clay creates compact blocks and glazed surfaces that restrict establishment.

In light soil, incorporate mature organic matter over a broad area and monitor watering more carefully during dry weather.

Planting a young container-grown serviceberry

A dormant serviceberry may be planted in autumn or winter whenever the ground is neither frozen nor waterlogged.

For a container-grown plant that is already in leaf, spring planting after the main risk of late frost avoids immediately exposing tender foliage and flowers to cold conditions for which they are not yet acclimatised.

A mature dormant shrub is considerably hardier than a young nursery plant carrying soft new growth. This does not reduce the general hardiness of the species; it concerns only tissues that have already begun growing.

Prepare a broad area rather than a small planting hole filled with potting compost. Loosen the soil, create a crumbly structure once it has drained and, for spring planting, allow the soil to begin warming.

Remove couch grass, bindweed, docks and other perennial weeds carefully. Serviceberries develop many feeding roots near the surface and compete poorly with dense grass during establishment.

Position the root collar at soil level and backfill mainly with the original soil. A moderate quantity of mature compost can be incorporated over a broad area where the soil is poor, but a pocket of pure compost or fresh manure does not provide better long-term establishment.

Water thoroughly after planting to settle the soil around the roots. Keep the surrounding area weed-free and water throughout the first year whenever rainfall is insufficient, not only during the first few weeks.

Organic mulch can conserve moisture, but it should not be piled against the stems. Keep the root collar visible and check the moisture beneath the mulch rather than watering according to a fixed timetable.

Watering and feeding

An established serviceberry tolerates moderately dry periods, but fruit production is sensitive to a lack of water.

Drought during flowering, fruit set or fruit swelling may reduce fruit size and cause part of the crop to drop.

Water young plants deeply whenever rainfall is insufficient. Frequent shallow watering encourages roots to remain near the surface and makes the shrub more dependent on future irrigation.

Serviceberries are not particularly demanding feeders. Excessively soft growth caused by heavy nitrogen applications may increase vulnerability to fire blight, aphids and foliar diseases.

A moderate addition of mature compost combined with healthy soil and suitable mulch is normally sufficient in a garden.

Before treating an apparent nutrient deficiency, first check drainage, grass competition and the actual moisture level of the soil.

Which wood carries the best crop?

Fruit production is concentrated on young, well-lit branches. In commercial Saskatoon plantings, stems approximately two to four years old generally produce the best-quality fruit.

An unmanaged clump gradually accumulates old, tall stems that are shaded near their base. The crop then moves towards the outside and top of the shrub, making the fruit more difficult to pick and protect.

Repeatedly cutting back every shoot removes wood capable of flowering and stimulates vigorous leafy growth at the expense of fruit production.

Pruning should create gradual renewal rather than forcing the shrub into a rigid geometric shape.

Pruning and renewing a fruiting clump

During the first few years, allow the shrub to develop several strong, well-spaced stems. Remove only damaged wood, badly crossing branches and suckers extending beyond the area allocated to the plant.

Once the clump becomes dense, remove a small number of the oldest stems at ground level each year to encourage vigorous replacements.

This method maintains regular production while allowing light and air to reach the centre of the plant.

Do not shorten every branch tip as though trimming a formal hedge. This creates a dense outer shell of small shoots, pushes fruit towards the edge and makes harvesting more difficult.

An old and unproductive clump can be rejuvenated by cutting it back close to the ground because serviceberries are capable of regrowing from the base. This temporarily removes the crop and should be reserved for genuinely old or badly neglected plants.

Serviceberries trained as small trees require lighter pruning. Maintain a balanced framework, remove basal shoots where a clear trunk is desired and avoid large cuts that damage the naturally elegant shape of the tree.

How to recognise fully ripe Saskatoon berries

The fruit normally changes from green to pink or red and then to dark purple. It is not fully ripe as soon as it begins to colour.

At the early purple stage, the flesh may still be firm, low in sugar and slightly astringent.

Fully ripe fruit has the characteristic colour of the cultivar, usually blue-purple to almost black with a light waxy bloom. It becomes slightly softer, develops its aroma and detaches without needing to be pulled firmly from the cluster.

Fruit within one cluster may not ripen simultaneously. For fresh eating, several picking rounds allow each fruit to be harvested at its best stage.

For cooking or freezing, a small proportion of slightly less mature fruit is normally acceptable.

Birds often begin eating the crop before the gardener considers it completely ripe. A rapidly disappearing harvest does not therefore necessarily indicate poor fruit set or premature fruit drop.

Protecting the crop from birds

Blackbirds, starlings and other birds are among the principal competitors for Saskatoon berries. Once they have identified the food source, they may remove the crop within a very short period.

The most effective protection is a properly supported net or fruit cage installed before the fruit reaches full colour.

Do not simply throw loose netting over the branches. It is difficult to remove and may trap birds.

Choosing a cultivar of manageable height and maintaining an open clump makes protection considerably easier. Complete netting soon becomes impractical when a serviceberry is trained as a large tree.

In a large garden, planting several shrubs may provide enough fruit to share part of the crop with wildlife, but this does not guarantee that birds will leave the best fruit within easy reach.

Flavour, uses and storage

Saskatoon berries can be eaten fresh, but their texture and flavour are often particularly well expressed after cooking.

They are suitable for pies, compotes, preserves, jellies, muffins, sauces and fruit desserts.

Their flesh generally retains its shape more effectively during cooking than a blueberry. This is useful in baking, where the fruit can remain partly intact rather than releasing all of its juice.

The fruit can also be dried or made into fruit leather. Its mild sweetness can benefit from being combined with a sharper fruit such as redcurrant, raspberry or a tart apple.

After picking, cool the fruit promptly. Fully ripe Saskatoon berries keep for only a few days in the refrigerator.

Freezing is a simple method of longer preservation and maintains their suitability for cooking and baking.

Diseases to monitor in humid climates

Which serviceberry should you choose?

For regular fruit production, choose a named cultivar of Amelanchier alnifolia. Compare flavour, fruit size, firmness, vigour, habit and suckering rather than selecting only the cultivar advertised as producing the largest fruit.

For eating fresh, choose a sweet, aromatic and large-fruited cultivar.

For pies, preserves or freezing, a productive cultivar with firm fruit and relatively concentrated ripening may be more practical.

For a fruiting hedge, a vigorous and freely suckering cultivar can quickly form a productive line of shrubs.

For a small garden or a plant intended to remain beneath netting, a compact cultivar that can be kept below two or three metres is easier to manage.

Where the primary objective is an ornamental small tree with an occasional crop, forms of Amelanchier laevis, A. canadensis, A. arborea, A. lamarckii and ornamental hybrids remain excellent choices.

Do not confuse the winter hardiness of the plant with security of the harvest. A serviceberry may be completely adapted to the climate yet produce little because of frost on the flowers, insufficient sunlight, ageing stems or birds removing most of the crop.