Arrive?
In some cases, invasive plants arrive purely by accident, sometimes they are shipped overseas. In other cases, invasive plants are selected for their horticultural attributes. They are also picked up by gardeners because they are so beautiful and planted in their gardens. There are many ways that allow the invasive species such as the Purple Loose-Strife and others to arrive here in North America and elsewhere. It all began way back in the 1700s when travel by boat became somewhat commonplace. One theory indicates that when the ships leaving the ports in Europe, where the Purple Loose-Strife is native, they needed to weight down their ships with ballast for the voyage across the Atlantic Ocean. In many cases, the ballast used was merely beach sand, which contained propagules such as seeds and plant parts of the Purple Loose-Strife. The sand\ballast was off loaded when some of the ships arrived in Long Island, NY by just dumping some sand onto the beach. This allowed the seeds to germinate and the plant parts to take root and hence being the cycle of population growth and spread. And that is how they arrive.
