Catherine StewartAgapanthus bites the dust

In warm temperate to subtropical areas, agapanthus have been the gardener’s friend for decades. Cheap to buy and easy to propagate, drought tolerant, low maintenance and reliably flowering through November and December, agapanthus can be found in most suburban gardens through east coast Australia. But I’ve just removed the last of mine as this previous stalwart is now an ugly liability. What happened?

agapanthus4

First, of course, agapanthus has a weed potential in cooler climates, such as the Blue Mountains, Southern Highlands and inland areas. Although there are newer varieties that are said to be sterile, like ‘Black Pantha’, I’ve not had much success growing these in my Sydney garden. Unlike the species, they do not seem to be particularly vigorous.

But for me, the sad fate of agapanthus doesn’t lie with its weedy tale but a two-pronged attack that makes it a garden liability.

agapanthus2First, there is the persistent mealy bug attack that turns its leaves into twisted, deformed ribbons instead of the strong, strap-like shape they should be. My agapanthus over the past few years have shrunk from being lovely large clumps of architectural strap leaves into pathetic, pale echoes of their former glory. The leaves are short, narrow, thin and with wavy edges, exposing the white leaf base and the many shrivelled old leaves which used to be hidden by the newer foliage.

agapanthus3

To add insult to this permanent injury, the perpetual debilitation sends the agapanthus leaves, once seemingly bullet proof on even the hottest days, into melt down. I’m assuming that the constant sap-sucking of the mealy bugs compromises that ability of the leaves to translocate sufficient moisture to protect them in heat waves.

 

The consequences, which you’ll see all over Sydney, are acres of burned agapanthus, shrivelled and white from a few over 40 degree days this past summer. Our once reliable, clumping ground cover is gone forever.

agapanthusSad, but no doubt partly our own fault from planting so many monocultures of this, and other, plants. I remember being warned during my landscape design course about the dangers of planting monocultures – that they would be like a huge ‘EAT AT JOE’S’ signpost for any voracious beastie or disease, allowing it to proliferate to obscene, devastating numbers, eventually becoming a permanent and impossible to control pest.

Did we listen? No. Has it happened? Yes. Will something else like this happen to another favourite plant? It already has – next instalment – the demise of the lilly pilly hedge.

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Catherine Stewart

About Catherine Stewart

Award-winning garden journalist, blogger and photographer; writer for garden magazines and co-author of 'Waterwise Gardening'; landscape designer turned landscape design judge and critic; compulsive networker and lover of generally putting fingers in lots of pies. Particularly mud pies. Creator, curator and editor of GardenDrum. Sydney, NSW.

21 thoughts on “Agapanthus bites the dust

  1. So sad……and definitely NOT happening here at Bilpin. Ours are thriving with Eastern Spinebills enjoying the nectar. “Purple Cloud” has been spectacular and the gorgeous species, Agapanthus inapertus with flowers that are almost waxy, is blooming now. Move on up.

    • You’re lucky, Peta, that your more elevated area with its cooler temperatures and lower humidity prevents mealy bugs from reaching such damaging numbers. However I love too many other things about my maritime subtropical climate to give it up!

  2. Kaylene on said:

    The same is happening here in Brisbane. Can’t the mealy bug be controlled? If this is a result of monoculture, could you replant with clumps of other species of Agapanthus? Or would the mealy bug just move on to the new species grown in the same space?

    • Parasitic wasps and lady birds are biological controls for mealy bugs but in agapanthus, the mealy bugs are right down inside the layers of emerging leaves so predators are unlikely to get to them in sufficient numbers. The same goes for sprays that need contact, like oil and soap sprays. A number of other chemical sprays that are translocated throughout the plants are registered for control of mealy bug but the pests reproduce so rapidly that resistance can develop within only a few generations.
      I don’t have either the time or the will to control pests on my plants with sprays and potions, especially to this extent, so I honestly think that just not growing agapanthus any more is a better long-term solution.

  3. Yikes, I’d planted these at my mum’s house as I thought they were bulletproof, but mine too have succumbed to mealybugs the past few summers. I’ve also noticed that a once healthy gardenia – about three metres away from the agapanthus – is now getting mealy bugs. Would they be coming from the agapanthus?

    • Well that’s certainly possible Ambra. Just like some plants attract beneficial insects, others no doubt do the opposite. At least on the more open form of a gardenia you have a better chance of controlling mealy bug.

  4. Adam on said:

    All I can say is Thank Goodness. Good riddance to bad rubbish. Over planted and pretty boring for most of the year, I won’t miss seeing these gone from tacky fast food and discount store carparks. – there are far more interesting things to plant!

    • The trouble with public carpark plantings is always the maintenance. There’s usually precious few dollars left in the budget, so anything deemed low maintenance is always going to end up there. You might like the alternatives a whole lot less.

  5. JenniP on said:

    You have my sincere condolences, Catherine. Here, in Western Victoria, we have many “missing teeth” in our aggie swathes following a series of searing 45 degree days some weeks back. They appeared to rally so well initially, but a week or so later simply collapsed and passed on. Gosh what a good lesson is the “Eat at Joes” sign; thank you for making us consider our mass-planting strategies in another light.

    • Yes, it does feel like the loss of an old friend. I’m glad not to look at their pathetic leaves any more but I miss them too.

  6. It’s been gnawing away at me, too, this summer, that my previously robust and glossy aggies, have lost much of their verve. Not mealy bugs, but definitely scorched and saggy yellowing leaves more abundant than previously noted. I love the damn things, weed or no, and will persist. I lhink the 40+degrees days we had here in January tested the toughest in the garden, and we will restore and return.

    • It may be something else reducing their vigour. I haven’t heard of any new agapanthus virus but anything’s possible – and even likely – when we use plants in massed groups all the time.

  7. Bernadette on said:

    Thanks so much for the explanation! We moved to Bunbury, WA about six months ago and the whole front entrance was resplendent with lovely agapanthus. Now they are a sad dried out mess and very burnt looking. I’m thinking to clear them all out and plant something else but can I rescue these plants and relocate them do you think? I’ve taken away most of the dried leaves but they almost feel too moist so I’m not sure if my issue is mealy bug/heat/overwatering! My sister arrives from the UK in a few days and I’d love to have the place a bit nicer!

    • You could try planting them where there’s more shade. They will still get mealy bug but they should withstand the heat better. They probably feel moist because of the loss of strength in the leaf. The leaves on mine used to feel thick and waxy, but now they feel soft and limp, which I guess you could describe as moist. I doubt that you could overwater agapanthus in Perth. They wouldn’t like to sit in wet soil but given your quick-draining soil that doesn’t seem likely. If you haven’t changed how you manage them, then something else must have. You could try adding some dianellas or liriope to the mix of strappy leaves.

      • Binoz on said:

        Thanks Catherine,

        I’ll give it a go when it cools down ( 30 again forecast for today!)
        Cheers

  8. Brian Holt on said:

    Hi Catherine, I’m a professional gardener and have struck this problem in 2 of my customers gardens. I tried applying Pestoil combined with Confidor and then followed up with Seasol. The results were a spectacular recovery in all cases.

    • Vera on said:

      Hi Brian
      Your treatment sounds encouraging; my Aggas have the same problem. Can you let me know what proportions of Pestoil and Confidor you use and how many applications? Also, when do you apply Seasol?
      Thanks
      Vera

  9. michelle maher on said:

    hi i have just purchased my agapanthus from ebay they survived the post trip but i put in pots till i decide where to plant 1 lot are turning from green leaves to white and droopy ? my potting mix is normal with a handful of cow manure ? pots are a good size
    i thought maybe i have over watered them or over fertilised them ? i can take a picture and send to an email adress if required thanks michelle of mudgee

    • Hi Michelle, it’s possible you might have overwatered them. Agapanthus can go rotten in such circumstances – the leaves become white then brown and slimy from the base. I also wouldn’t add cow manure to potting mix. Fresh potting mix is already very high in organic matter and doesn’t need more, and cow manure needs to be well composted before you introduce it to plants. If you’ve bought cheaper potting mix, it doesn’t have the added slow release fertilisers of the more expensive ones so you could add a sprinkling of that after you’ve given your plants a month or so to adjust to life in their new home. The problem might also be a feature of the pots you’ve chosen. If they are in shallow pots, the potting mix won’t release enough drainage water and agapanthus would likely rot.

  10. James on said:

    Please don’t use Confidor which is toxic to bees and banned in Europe. There’s an now alternative available at Bunnings called Eco-Neem.

    • Yes James, although neem oil is not yet registered in Australia for use on mealy bugs, it’s proving effective against a very wide range of pests and it’s registered for use on mealybug overseas.

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