Isotoma axillaris, also called Laurentia or Rock Isotome, is the only plant I have in drifts in my garden, because it really does look incredible en masse in garden borders. 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. They are short-lived but since they self seed you will not notice.

They are adaptable to different soils although do better with good moisture during the flowering season.

The most important thing to note about Isotoma is that the stems have a very irritant sap inside when broken. Even young stems exude this nasty sap, so you must choose your planting location carefully. Keep them in a high pot or raised bed if you have animals in your yard who like to get too close to plants. Don’t plant them if you have very small children or someone who likes to get touchy feely with your garden, as the sap is very irritating if rubbed in the eyes.

If you’d prefer a variety of Rock Isotome that doesn’t self seed as readily, then I recommend looking for Isotoma Fizz n Pop or Pop & Fizz. There is a pink variety and also a beautiful deep purple hybrid called ‘Glowing Violet’. These hybrids are very hardy and were a star performer when the Sydney Botanic Garden tested them in their trial garden a few years ago. They are easy to grow just about anywhere along the east coast, and even doing well in my sub-tropical garden in SEQ.

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.

Isotoma are tough and will even grow happily in tiny gaps between brick pavers! 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. They do like regular water during the flowering season. They will droop and look sad if left to go dry, but spring back to life as soon as they get some water.