The Boysen Berry has a dusty purple coloured fruit measuring approximately 35mm long and from 20-25mm in width. The growing habit is that of a trailing vine. These vines measure up to 6-7 metres in length on a well established bush. They do not crop quite as heavily as the youngberry, although this fact is compensated by the larger sized fruit.
Boysenberry leaves start appearing early in September, it flowers in mid October and the fruit ripens in mid December and continues into January. The fruit needs to be picked every four to five days. New canes appearing in mid October grow vigorously and should be pegged out of the way so they will not be trampled on. After harvest allow them to grow freely.
Boysenberries have been grown in Victoria for over thirty years, the commercial area is declining rapidly owing to the somewhat time consuming taking of “putting up” the canes
Preparation of Soil
Start preparing the soil in January with a good dressing of about 2kg per square metre of fowl or animal manure, then work this well into the soil. In February apply a dressing of artificial fertiliser such as N.P.K. 8-11-10 or N.P.K. 12-5-15 at the rate of 100gms per 1 square metre. Care should be taken to keep the area free of weeds, particularly perennials such as couch grass.
Planting Time and Spacing
June and July are the ideal months to plant. Plants should be spaced out at 2.5 metre intervals in a straight row. The plants look rather small and thin when you buy them, but they will grow vigorously. It is preferable to use black plastic sheeting along the row to control weeds. Cut small holes of 10 x 10 cm in the plastic sheet and dig holes about 15cm deep in which to plant the canes. This is most important in the period from February to April so that canes do not have to compete for survival with the fast growing weeds.
Manuring and Cultivation
In early September of the first season of growth apply another light sprinkling, about 200gms, of N.P.K 12-5-15 around the bush, ensuring that manure is not placed on any new cane shoots. In the second and following years apply 400-500gms of N.P.K. 12-5-15. Further dressings of organic manure should be made each July/August with monthly cultivation. Use a sharp hoe to keep large weeds down to a minimum. If the rows are on plastic sheet, keep weeds down around the base of the plant by removing by hand.
Pruning and Trellising
Trellis erection should be made at the end of the first season around May or June. The boysenberry has no support in itself and therefore needs a strong trellis to take the weight of the fruit bearing canes.
Treated pine posts 15cm x 2 metres are ideal. Dig holes 70cm deep to hold the most securely, place a 2cm steel post at 4 metre intervals along the row, hammer these down about 40-50cm then attach wires and pull tightly. In June/July the “putting up” operation commences. Using heavy leather or rubber gauntlet gloves, begin by straightening out the canes which spread all around the bush and lay them in one direction. Be very careful not to snap any canes. Standing close to the wire, gather the canes up together and thread them over the wire. Wind the canes around and along the wire generally about three times. Hang the last 20cm of cane down so that it can be pruned off. Tie the canes down to the wire with heavy string or binder twine in at least three or four positions. The next season these canes should be cut as close to the ground as possible and strings and canes removed together with wires. Repeat the “putting up” process with new canes.
During late November and early December new canes will be growing quickly from the base of the plant. In order to prevent any damage to these canes aging the pickling season they should be placed along under the bush and held back with stakes. Alternatively the canes could be tied together from each side with bindertwine.
Depending on the area, watering may be needed from late October through until March. In Victoria, for most seasons, conditions are reasonably moist up until December, when weekly watering may be necessary. After New Year, in the drier period, weekly watering are a must, in order to keep the new canes strong and healthy even though the crop will have finished. Both overhead and trickle irrigation systems are ideal for boysenberry cultivation.
If in December when your fruit is cropping and temperatures are approximately 33?C it is a good idea to water with overhead sprinklers for an hour or so to cool down the atmosphere and to prevent sun scorch on the berries
When the canes are tied up in July, spray Bordeaux mixture (copper sulphate and limil) at the rate of 1.5gms per litre of water. After leaf burst and before flowering, apply Thiram at the rate of 1.5gms per 1 litre of water every four weeks. This will check canespot and anthracnose diseases. When flowers appear look for thrips. Breathe gently over the flowers to cause the thrips to become more active (look at identification). If they are present spray with Rogor or Malathion sprays carefully, spray only if they are present.
Number of Plants Required
By the third season boysenberry plants should be in full production. Yielding up to 1500-2000gms per bush, five to six plans should be adequate for most familie