What is it?
This tough South African import is not the sort of immigrant that our environment needs. With its shiny, leathery, dark-green leaves and umbrella shaped clusters of purplish-blue or white flowers, it has won the hearts of many a gardener who wants a hardy plant for difficult areas with poor soil.
Why is it wicked?
Not content with the niche that it has carved out for itself as a ‘motorway plant’ on traffic islands and steep banks, agapanthus has spread into a variety of natural areas, where its thick root system crowds out any other species. It’s a particular problem in coastal areas where it has been planted in gardens; in these areas it can spread to sandy areas where it rapidly colonises dunes and cliff faces, threatening native plants that would normally grow in these areas. Agapanthus is spread by humans moving it from place to place, and by seeds spread by wagter and soil movement.
What can you do?
If you are determined that agapanthus has a place in your garden, take the simple step of deadheading the plants before the seed sets, and ensure that any roots that are dug out are disposed of at a refuse transfer station. If you want to make your place an aggie-free space, you can dig the plants up, or spray either the cut tops of the root systems, or the foliage itself. For more control information, check out www.weedbusters.org.nz
Try native renga renga lily (Arthropodim cirratum) with its strappy leaves and drooping white flowers, or one of the many small flaxes with various foliage colours. For non-natives, what about turf lily (Liriope muscari) or day lily (Hemerocallis species except H. fulva). Your local garden centre will be able to advise on suitable non-weedy species for your local growing conditions.