What’s making swan plants get sick and die?

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  • #57572


    I’m sure this is covered somewhere else, but I don’t know how to search for it so please forgive me starting a new topic.

    I’ve been growing swan plants for decades and have loads of them. But this year, for the first time ever, I’ve new growth yellowing, some twisted looking leaves and some flower bud clusters that look unhealthy. The affected plants are also losing leaves and then, within a couple of weeks, just turning to brown sticks. I’ve had a close look and can’t see the usual culprits like aphids, mites or thrips. There are no fine cobwebby bits or sticky residues or ants crawling over the plants farming their dairy cattle.

    The plants are all growing in the open ground and in full sun (in Western Springs, Auckland). They’re grown from seedlings that naturally sprouted in the garden from previous generations of plants on the same ground. We had butterflies right through Winter and there are some still out there today so I’m keen to get the plants healthy and keep the food supply going if I can. Most of the affected plants are from a crop of seedlings that came up three Springs ago.

    Is anyone else familiar with this, and knows the likely causes and possible treatments? I’m wondering if it might be a fungus but can’t see anything on the outside. I’m grateful for any suggestions.

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  • #57891


    yellow dying swan plants – sounds like scale bugs. if there is ants thats also an indicator along with wasps. if there are scale bugs the plants will be sticky to touch have black sticly mould and black holes in the stalks where the bugs bury in to eat the sap. you can treat the plants if you want to save them by smothering all life on the caterpillawrs included by spraying the whole plant with mineral oil conqueror oil spray. You have to get rid of them if you want new plantsto not get infected – its a bugger. If its a small infestation hen you could try and get rid of them by hand without spraying .



    I’ve discovered that any dying swan plant has little or no sap running through it. From any cause. When my plants are stripped of leaves I trim the top and if sap is running I know its worth the effort to try and regrow, little or no sap and I chuck it.



    Over the past year I have slowly lost around half of my swan plants from what sounds like the same thing. If you cut into the “sick” looking branches you’ll find there’s little/no sap flowing through the plant. I haven’t been able to work out what is causing it.



    Megan – perhaps take a branch into Kings St Lukes and ask their Plant Doctor… they may have seen something that you’ve missed. You could also do soil samples… but not sure how much that costs.



    my guess would be a virus … but its only a guess. whatever the case sounds like once a plant is affected its going to die so I’d pull them out and destroy them so they cant infect other plants.

    I’ve lost plants from being too wet/not draining properly. But its different symptoms to what you describe.

    good luck

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