With significant rainfall and cooler temperatures in late spring/early summer, conditions were optimum for blackberry germination and growth. From September to November young canes emerged from the crown or base of the blackberry bush and grew rapidly at a rate of between 5-8 cm per day.
By the end of November and into December plants were in full flower and in early January bushes were full of berries (fruit). As a general rule, in mid-late December the level of control using herbicides is effective as plants are yet to set fruit (seed), they are actively growing and are less likely to be heat stressed than in mid-summer. However its worth noting that if conditions are suitable, herbicide can be applied from flowering right through to fruiting – usually December, January, February and March.
In hot, dry periods currently being experienced across South East Australia hold off spraying plants with herbicide if they are showing signs of moisture stress i.e. wilting. Hot conditions during the day (i.e. over 30 °C) can temporarily stress plants and limit uptake or absorption of herbicides. During hot conditions, spray in the morning before 11am or wait until weather conditions are milder.
