Tag Archives: roadside weeds

A moderately controversial opinion, in New Zealand at least

The convolvulus is potentially a bigger problem than the agapanthus

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?

These plants are likely to stay on the roadside, rather than moving across the fence onto farmland

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.

Showing my age, apparently, I have agapanthus in the garden

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.

We rate the montbretia (Crocosmia x crocosmiiflora) as a worse weed than the agapanthus. It is certainly harder to control, let alone eradicate and it spreads like wildfire

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.

On the verges

Agapanthus with the dreaded convolvus - the latter is pretty in flower but we do not need it

Agapanthus with the dreaded convolvus – the latter is pretty in flower but we do not need it

As you drive around the countryside in January, ponder this: does a sprayed roadside with dead grass and roadside litter look better than wildflowers? And are garden escapes (which takes in most roadside plants and flowers) environmentally worse than repeated application of weedkiller? Maybe it is time we reviewed our attitude to weeds.

It is often said that a weed is simply a plant in the wrong place, though I see Sara Stein is attributed with the extended statement, “A weed is a plant that is not only in the wrong place, but intends to stay.” After all, even weeds are native to somewhere and one country’s treasure can be another country’s problem.

Toetoe beside the new Waikato expressway

Toetoe beside the new Waikato expressway

A disclaimer first: our native bush and forest are precious and vulnerable to takeover by invasive and aggressive imports. We do not need another old man’s beard (Clematis vitalba) and perish the thought that Japanese knotweed (Fallopia japonica) ever gets a major foothold here. If you are lucky enough to live adjacent to near-pristine native bush, that brings an obligation to be very careful with what escapes your property and colonises roadsides. It also behoves us all to have some awareness of what is on our Regional Council banned and watch lists.

But most of us live in heavily modified environments and I suspect a preference for weedkiller over wildflowers arose from our farming heritage and feeling of obligation that “weeds” should not be permitted to invade precious farmland. Nowadays, when farming has become much more industrialised – a green desert, often, lacking even shelter belts – based entirely on imported grass and feed species, I don’t think that argument holds.

The ugliness of the sprayed  verge

The ugliness of the sprayed verge

Each time we visit Britain, we are entranced by their hedgerows and natural roadside vegetation. Apparently, after major clearance in decades past, there came an awareness that hedgerows contribute a great deal to the eco-system and grants were made available to reinstate them. There is not widespread mowing of road verges, let alone the ugliness of spraying. Would that we had such an enlightened attitude here. In vain do we protest that repeated spraying creates a vacuum into which unwanted weeds move first (notably the invasive, yellow bristle grass in Tikorangi), but it also prevents the ground from absorbing rainfall. Instead, the surface water is funnelled down drainage ditches, washing with it weed spray and any petrol residue from the road into waterways. How much better to have a growing roadside which filters the run-off?

Crocosmia - weed or woldflower?

Crocosmia – weed or woldflower?

Roadside vegetation is more interesting visually too, offering flowers and seasonal colour. Add to that a wildlife corridor role and we argue that they can make a significant contribution to a healthy environment. If you are worried about using imported ornamentals, you can encourage native re-vegetation. The native plantings alongside the new Waikato Expressway feature an abundance of toetoe which is wonderfully sculptural and interesting, especially silhouetted against the sky.

But we like the random mix of plants and colours we see. I look for the point where wild hydrangeas on the Otorohanga bypass change from blue tones to pink tones. I guess that marks the transition to limestone country. All our hydrangeas in Taranaki are blue as blue and they thrive on roadsides in a climate where we get summer rainfall.

005The white Japanese anemones that flower in the long grass around the country corner where we live make me smile every autumn. Orange-red crocosmia – earlier referred to as montbretia – feature large around here. So too do red hot pokers, fennel, arum lilies and cannas while further north the ox-eye daises, yellow vetch and wild carrot feature more.

012And agapanthus. There is a plant that is a great deal more revered overseas than here. It is controversial, actively discouraged and some forms banned in northern regions. Some folk hate it with a passion and it cannot be sprayed out with glyphosate. But truly, our roadsides round here would be the poorer without the summer display. In its defence, we have not seen this tough plant seed down any great distance from its parent in our conditions and it is also very good at stabilising clay banks.

I recall two English garden visitors a few years ago who asked what were the “giant bluebell and what looks like a lace-cap yellow hydrangea” flowering on all our roadsides. The yellow lace-cap was fennel but the giant bluebell had me absolutely stumped until I next drove out. It immediately dawned on me that they were referring to agapanthus. It is not cold-hardy in large parts of Europe and the UK and is a prized garden plant. No wonder they failed to identify it growing wild in abundance here.

abbie 20 10 2015 copy

Fennel, not lace cap hydrangea

Fennel, not lace cap hydrangea

First published in the January issue of New Zealand Gardener.