Isotoma axillaris

Native Plant of the Week – Isotoma axillaris

This week’s favourite started flowering in my garden in late October and is still looking beautiful in mid December, even after unseasonal heavy late spring rains.

Isotoma axillaris is the only plant I have in drifts in my garden, because it really does look incredible en masse. It seems to know that, as it self seeds readily in a dense pattern around each plant so just a few plants spaced out in your garden will naturally turn into a drift in a year or two, if you don’t pile up too much mulch between them after they finish flowering and set seed.

There are many great cultivars available, but I love the original native variety the most. It has starry pointed petals that open as bright purple and slowly fade to a soft pastel tone. The flowers sit on tall stalks around 40cm high and each plant produces a cluster of stalks and flowers without the need for tip pruning the first year – although you will get better blooms in the second year if you give them a chop back after flowering.

I was nervous about planting Isotoma originally, as I had read that the sap is very irritating to skin and eyes. At first I planted it in a pot, so I could keep it away from the pugs since they are prone to getting things in their bulging eyes anyway, so I feared this plant might be too risky. The little branches are quite brittle. They break readily and release the problem milky sap. I often end up breaking them when trying to weed around them.

Eventually I plucked up the courage to plant them in the garden, and I’m mighty glad I did. They look spectacular when mass planted and the height and density seems to keep our pug Maisie out of that section of the garden. The mass planted look in my garden this year was achieved by transplanting many of the self seeded plants from last year. Moving them to where I wanted them was easy when they were small and most survived the move without any trouble.

A benefit of Isotoma axillaris is their native bee attracting qualities. I find the Blue Banded Bees don’t turn up to our garden each year until the Isotoma are flowering. I don’t know if this is because of the mass of colour or the strong pollen scent. They visit daily through the flowering season, through multiple generations which is lovely to observe.

I have found Isotoma axillaris mostly unbothered by pests, although this year some fat green caterpillars are making a meal of it. There are so many flowers that it isn’t that noticeable. So I am ignoring the damage as I look forward to seeing the butterflies or if nothing else they will provide a hearty meal for the birds. I’ll just cut them back hard after the flowering finishes anyway, so perhaps the caterpillars are just making a start on that job for me?

Isotoma axillaris will make a great plant for pots in a cottage garden too. They are adaptable to different soils although do better with good moisture during the flowering season.


  1. Barbara Rix

    Hi Rae,
    I have just discovered your site, blog etc. I am delighted. I am a lover of Australian natives. I take as many photos as I can wherever I am. I love creating art and in particular drawing native plants, botanicals but not in the traditional way. I do very detailed works. I am always looking for different plants but am not able to locate many from outside my local area of SE Qld. I am impressed with your beautiful photographs & wonder if you might allow me to use some of your images to draw. I am very aware of copyright rules and laws and do not work outside these. I am an avid Pinterest user and my name on that is Barbara Ann. I have created many boards with Australian natives eg Australian Herbaceous Plants, Australian Shrubs > 1m, Art of Australian Flora & many more. I have yet to set up a website, blog etc. I work mostly in coloured pencils & have a Section in my board “Artists of Coloured Pencils”.I have recently purchased a new iPad Pro & Apple pencil so hope to start using Procreate. ‘

    • Rae

      Hi Barbara, I’m finally dropping a reply here so you and other artists know. I am very happy for any artist to use my photographs as reference material. If you get in touch I will happily send high res versions too. How are you going with your iPad and pencil? I love using them to draw and paint – see a recent Ajuga australis drawing on my Instagram that was done on an ipad using procreate 🙂


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