Establishing the risk of invasive weeds spreading
Because of the wide range of propagules, for each invasive plant species it is important to establish where the risk (of spread) lies.
For invasive plants which spread through wind dispersed seeds we can try to manage the risk by stopping flowering/seed development processes altogether. But seeds persist in the soil too and can survive for long periods, especially if the soil is subject to disturbance and the seeds get buried.
The so-called seed-bank can be exhausted over time with various low-impact interventions, but the risk of re-colonisation never goes away completely (new seed imports from surrounding area). But potentially, if time is available, the waste generated is zero (no need to remove soil from the location).