Grow Swan plants for the Monarch Butterfly


Monarch butterflies are amazing creatures. They aren’t native to New Zealand – they arrived here in the late 1800s – but they’ve become so much at home we’ve adopted them as honorary Kiwis.

And, because they supply food for the larvae of the monarch butterfly, swan plants are favourites with New Zealand gardeners. Seeds for swan plants are found in Yates packet seed range. Look on the Yates stand for the packet illustrated with the swan plant’s bladder-shaped pod and with the little butterfly logo in the corner. That’s a reminder that, for every packet sold, Yates makes a donation to the Monarch Butterfly Trust, an organisation that encourages and supports the butterfly. Visit for more information about their amazing work.

Monarchs much prefer the warmer weather, which is why spring is the time of year to get your swan plants started. In many areas it’s probably a little cold to germinate the seeds directly in the soil, so it’s best to start them in pots filled with Yates Black Magic Seed Raising Mix that can be kept in a warm indoor spot.

Sow more seeds every few weeks so that you’ll have plenty of food for the hungry caterpillars through until autumn. Transplant the plants carefully when they’re big enough it handle. If you can find a sheltered, warm outdoor spot, they can go outside but, in colder areas, you’ll have to keep growing them indoors or in a glasshouse for some weeks yet. But during the warm weather the butterflies will be delighted to find swan plants in your garden. Just remember to check and remove excess eggs so that there’ll be enough food for the remaining two or three caterpillars to eat.

After they emerge, the caterpillars will start feeding at the base of a leaf. This is so that some of the toxic sap can drain away. Mind you, the adult butterflies turn this toxicity to good use – it makes them taste so bad that predators like birds leave them alone.

Like all caterpillars, monarch larvae eventually become eating machines. They grow out of their own skins a number of times before they find a spot – preferably out of full sun – to hang and pupate. To watch their progress, you can make a protective enclosure out of a box frame with a solid roof and sides covered with netting. Hopefully the pupae will attach themselves to the roof of the enclosure. Make sure the sides of the cages are lifted as the butterflies emerge (two to three weeks later).

A couple of hours after emergence, they’ll be ready to take their first flight. You’ll then have the joy of watching the butterflies flitting about your garden, no doubt looking for more swan plants. Have some seedlings growing on because, as the weather warms, butterfly numbers will increase.

Keep the plants growing vigorously by feeding with some liquid Thrive that can be watered over the root system. Don’t apply fertiliser to the leaves and definitely don’t spray with any pesticides. Aphids, the most likely pests, can be controlled by squashing between thumb and forefinger.


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