Most of us know that Agapanthus are hardy plants that flower for a long time. This is probably why they are planted so often on bush properties, especially along driveways. The blue or white flowers are attractive but they do set a lot of seed.
The plants are reasonably hard to get rid of and out compete native plants in bush settings. They also seem to attract a lot of snails and slugs. Some references on the internet mention that parts of the plants are toxic.
For those who persist in keeping or planting these environmental weeds, please cut off the seed heads before they develop and spread into the surround bushland. Sterile plants are available.
At the Melbourne Flower Show recently I found the answer for those of you who are too lazy to cut off the heads. Buy or make some nice metal flowers. They are expensive but so is the cost of removing them from bushland.