by Sara Williams
Raspberry flowers have both male and female parts and are self-fruitful meaning that two cultivars are not needed to set fruit. Flowering occurs over a four-week period and bees are the main pollinators. Avoid using insecticides.
Fruit takes 30 to 45 days to develop, depending on the cultivar and weather conditions. Since the greatest increase in fresh weight occurs in the final 7 to 10 days of fruit development, watering at this time is beneficial.
The fruit should be harvested when just ripe as no further ripening occurs once the berry is picked. Berries usually ripen in July or August. A ripe berry is red (without darker colouration), plump, firm and sweet and separates easily from the receptacle when picked. Raspberries reach a peak of maturity quickly, maintain top quality for a few days and then deteriorate. Fruit quality is usually highest at the beginning of the season when berries have a higher fresh weight than that of fruit produced later. They are very perishable and should be harvested early in the morning (but after dew has evaporated) and cooled immediately. Raspberries should be picked every 3 to 4 days.
Modern raspberry varieties include genetic material from both the Old and New World. Old World selections contribute good fruit quality and New World selections hardiness and tolerance of heat and cold.
The following are a few of the cultivars that have been developed specifically for prairie conditions. Other varieties are worth trying, but start with just a few to see if they will grow well for you in your location.
‘Boyne’ is one of the older but most frequently grown raspberries on the prairies. Developed at the Morden Agricultural Canada Research Station in Manitoba, it is hardy and consistently productive. Canes are medium height, thick, erect, and stocky, with many lateral branches. ‘Boyne’ suckers freely. Fruit is medium-sized (1.6 cm / 5/8 in. diameter), dark red, juicy, aromatic and tart. It is very good fresh or frozen and excellent for processing.
‘Red Mammoth’, from the University of Saskatchewan (1999), has firm juicy, bright red berries that are easily picked and produced over a long period. The fruit is larger than ‘Boyne’ (2.15 cm / 7/8 in. diameter), sweeter, and higher yielding. It has good vigour and is hardier than ‘Boyne.’ The drawback: canes are less sturdy and require trellising for support.
‘Steadfast’, another University of Saskatchewan selection, has very little suckering, making it ideal for smaller urban gardens. The fruit quality is similar to ‘Boyne’. The round, bright red berries are easily detached, produce over a longer season, but are lower yielding. Cane sturdiness is similar to ‘Boyne’.
‘Red Bounty’, also from the University of Saskatchewan (1999) has large (1.99 mm / 0.8 in.), flavourful, round bright red fruit that is excellent for processing and easily detached for picking. Hardier than ‘Boyne’, the canes are of medium stature, but less sturdy and require support.
‘Honey Queen’, developed many years ago by Robert Erskine of Rocky Mountain House, Alberta, is a sweet, golden yellow berry with a unique taste, excellent for fresh eating and with ice cream. It does not freeze well but is said to make excellent wine.
Fall-bearing raspberries such as ‘Double Delight’ produce fruit late in their first season. Worthy of trial in a protected location if space permits, they are generally not reliable unless our growing season is prolonged without near or below-freezing temperatures.
Sara Williams, with Bob Bors, is the author of Growing Fruit in Northern Gardens.
This column is provided courtesy of the Saskatchewan Perennial Society (SPS; email@example.com ). Check our website saskperennial.ca) or Facebook page (facebook.com/saskperennial). All Saskatchewan Perennial Society events are on hold until further notice.