Blackberry invasion and establishment is reliant on three factors, firstly that there is a place for it to grow, secondly that it has a way to get to that site and thirdly once at that site it has the ability to compete with other plant species to enable establishment. Blackberry is unlikely to establish where other plants have the opportunity to out compete it, hence blackberry usually establishes where competition is removed or reduced to such a level that the weed has an advantage. Invasion of blackberry is most likely after disturbance, the greater the degree of disturbance the greater likelihood of invasion. In summary, the worst blackberry problems are often in areas where there is bare, soft soil, high nutrient availability, moist conditions, and high light intensity.
Mechanisms that enable blackberry’s propagules to spread include:
- The ability to be spread by water
- The ability to be spread by attachment
- The ability to be spread by birds and other animals that eat it.
- The ability to be spread intentionally or unintentionally by humans.