We like roadside agapanthus in our area. The sight of blue and white in abundance is a summer pleasure. It has become one of our wildflowers.
Why controversial? I have watched comments on Twitter in recent weeks, railing against the horrors of agapanthus and what a ghastly plant and flower it is. This happens every summer. One tweeter even declared that ‘nobody born after 1972 can bear agapanthus’. At least, I think it was 1972, or thereabouts – presumably the birth year of the tweeter. Reader, I was born somewhat before 1972 and it felt like an ageist attack.
I grow old
I grow old
I shall watch my agapanthus blooms unfold
I get that some people don’t like agapanthus and that it isn’t the world’s greatest plant to inherit en masse in a garden. What I don’t understand is the level of visceral hostility, the intensity of emotion expended on a plant that is moderately benign and consistently blooms in summer. I don’t engage in these Twitter diatribes but I did want to ask what they would prefer to see – mown or sprayed roadsides bereft of flowering weeds? Did they think agapanthus worse than convolvulus, montbretia, woolly nightshade, fennel, chicory, kniphofia, hydrangeas, canna lilies, pampas grass or many other plants that escaped onto our roadsides? Why single out agapanthus?
Given the huge amount of agapanthus we have naturalised in our area, I can say that I have not seen it invading farmland. It is not like pampas, woolly nightshade or montbretia which will colonise new territory the moment your back is turned. Because the seed is so large, it doesn’t spread itself around on wind and does not appear to be spread by birds. Nor does it spread below ground so it doesn’t tick the invasive boxes in our book. It increases from the base rhizomes and by seed but the heavy seed drops near the plant. It can be spread by water so maybe take care and eliminate by waterways and drains if you are worried about spreading it further. We get out and deadhead our roadside agapanthus.
Agapanthus used to be promoted because it is such an easy-going plant, tolerant of full sun and shade and it is useful in retaining loose soils on banks which could slip if left bare. It is not caustic and it is pest-free. It isn’t an exciting plant when not in flower, but I welcome that expanse of blue and white blooms in summer. I guess it is that very adaptability that has made it a pariah, a noxious weed, some declare, that needs to banned, NZ’s worst weed, even, in some eyes.
I like it enough to have selected a good dark blue form from the roadside which I brought into an area of the summer gardens where tree roots made the ground somewhat inhospitable for choicer perennials. After all, I was born before 1972. I deadhead after flowering before the seed has ripened, putting the spent flower heads in deep shade (not the compost heap) and we root prune the clumps in winter to stop them getting too large. But then, I also like wild fennel enough to have used that in the summer borders, too.
If you do happen to have giant clumps in your garden that you want to get rid of, you need to understand that it is immune to the common herbicides you can buy over the counter. It is most likely you will need to dig it out but don’t make the mistake of trying to dig it all out in a massive clump. First sharpen your spade. A sharp edge makes a huge difference. Then start slicing through the clump from the outside, removing it in manageable pieces. It is not deep rooted and the base of the clump (the rhizome) and the roots are fleshy, so easy to slice.
Don’t put the bits straight on the compost heap because most will grow again. Cut the leaves off – those can be composted. If you are doing it in high summer – like now – turn the remains of the clump – all the white bits – upside down on a dry surface so the roots face the sun and dry out. In cooler months you can stow it under cover so it dries or pile it in a black bin bag and lie that on concrete in the sun so it heats up and composts. I have taken all of the above steps and it is not that hard.
Mark has just suggested that he thinks you could get away with slicing it off right at ground level (the rhizomes are usually sitting above the ground) and leaving the roots behind. It is not like alstromeria, tradescantia or montbretia where every piece left behind will grow again. We haven’t tried this approach but if you want to, you may be able to achieve agapanthus elimination with a heavy knife or meat cleaver. Just go back and check from time to time that nothing is sprouting afresh.
There are many worse plants to eliminate than agapanthus but we are happy to stick with the plants we have and just keep them under control.