Plant Profile: Commelina diffusa – Climbing Dayflower

Just look at that beautiful deep blue!

Also known as:

  • Commelina cyanea (in New South Wales, possibly a different species, scientific analysis ongoing)
  • Scurvy Plant 
  • Native Wandering Jew
  • Creeping Christian
  • Climbing Dayflower
  • Spreading Dayflower
The original specimen which caught my eye on the dam wall.

Growing conditions:

  • Part shade/Shade
  • Tolerant of most soils
  • Groundcover (can become invasive in good conditions)
  • Suitable for rockeries and hanging pots
  • Perennial in tropics and subtropics, annual in warm temperate climates
The petals on these so-called dayflowers start the day spread wide and slowly close. On my dam wall the flowers have vanished into withered blue clusters by 3pm.

My first recollection of this species is dominated by a catch of breath as I spied a delightful deep blue flower on my dam wall. This was followed by a resigned sigh, with a flower like that and the fleshy green stems it was probably an exotic invasive! I put off identifying it which I do sometimes when I am enchanted by a new species.  Often I find out that for the good of the biodiversity in my garden I must remove the plant. A couple of months later I was browsing the Queensland Plant Identification Facebook Page when my eye caught the same blue flower! As I read through the discussion in the comments I was delighted to discover that it was native! Even better, the flower was more vibrant than its exotic cousin which also grows on my dam wall! I set out to isolate the populations of each species and started propating the native to replace the exotic. You can read my comparison of the species by clicking here.

The Facebook post that helped me with my initial identification. Posted with permission from Andrew Kopp.

I use this plant for erosion control as it’s happy on a steep slope and provides great biodiversity benefits, like habitat for invertebrates and soil coverage as well as food for kangaroos, bandicoots and bettongs. It propagates easily from the brittle stem segments. Indeed if you try to remove it, you need to get every part of this plant or they will likely reappear.

This stalk had two blooms, but by the time I went to take photos at lunchtime, the lower one had already diminished to a tiny blue crumple.

Apparently Captain James Cook gave this plant to his sailors to eat in order to prevent scurvy. The new leaf tips are reported to taste like bitter lettuce.

A Factsheet published as a part of the Australian Tropical Rainforest Plants Edition 7 (RFK7) lists the following uses:

  • Juice being used to cure wounds, for inflamed eyes, as part of an external remedy for bone fracture and as a digestive aid (Smith 1979).
  • Women rub their hair with it in the Torres Strait area (Lawrie s.n.)
  • Within China it is used as a medicinal herb with febrifugal and diuretic properties. A dye is also obtained from the juice of the petals for use in painting.

Wishing you weeds you don’t have to pull out,

janegrowsgardenrooms

Additional: recently I have found out that people plant these near their chicken pens. Apparently they LOVE to snack on them!

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