Isotoma fluviatilis (Blue Star Creeper)

Isotoma fluviatilis (Blue Star Creeper) after I brought it home on 6-10-18, #457-5.

Blue Star Creeper, Swamp Isotome

Isotoma fluviatilis

Eye-SOT-oh-muh   floo-vee-uh-TIL-iss

Synonyms of Isotoma fluviatilis (3) (Updated on 12-13-22 from Plants of the World Online): Laurentia fluviatilis (R.Br.) E.Wimm., Lobelia fluviatilis R.Br., Rapuntium fluviatilis (R.Br.) C.Presl
Synonyms of Isotoma fluviatillis subsp. fluviatillis (14)(Updated on 12-13-22 from POWO): Enchysia baueri C.Presl (1836), Enchysia baueri var. major C.Presl (1836), Enchysia gaudichaudii C.Presl (1836), Enchysia lessonii C.Presl (1836), Hypsela sessiliflora E.Wimm. (1943), Isotoma fluviatilis var. inundata (R.Br.) Benth. (1868), Isotoma sessiliflora (E.Wimm.) Lammers (1999), Laurentia baueri (C.Presl) A.DC. (1839), Laurentia baueri var. major (C.Presl) A.DC. (1839), Laurentia fluviatilis var. inundata (R.Br.) E.Wimm. (1948), Laurentia fluviatilis var. lessonii (C.Presl) E.Wimm. (1948), Laurentia gaudichaudii (C.Presl) A.DC. (1839), Lobelia inundata R.Br. (1810), Rapuntium inundatum (R.Br.) C.Presl (1836)

Isotoma fluviatilis (R.Br.) F.Muell. ex Benth. is the accepted scientific name for the Blue Star Creeper. It was described as such by George Bentham in Flora Australiensis in 1868. Mr. Bentham gave Ferdinand Jacob Heinrich von Mueller credit for previously naming the plant and using his description. It was PREVIOUSLY named and described as Lobelia fluviatilis by Robert Brown in Prodromus Florae Novae Hollandiae in 1810. 

Accepted Infraspecific Names (3): Isotoma fluviatilis subsp. australis McComb, Isotoma fluviatilis subsp. borealis McComb, *Isotoma fluviatilis subsp. fluviatilis (autonym). *When an infraspecific taxon is named, an autonym (“type-specimen”) is automatically generated whose description is closest to the (original) species. All have their own list of synonyms… In this case, only the species and autonym have synonyms.

The genus Isotoma Lindl. was named and described by John Lindley in the Botanical Registry in 1826. 

As of 12-13-22 when this page was last updated, Plants of the World Online lists 10 accepted species of Isotoma. It is a member of the plant family Campanulaceae with 94 genera. Those numbers could change as updates are made on POWO.

Some websites list this plant as Laurentia fluviatilis but that name is now a synonym of Isotoma fluviatilis. The genus Laurentia is considered a synonym of the Lobelia genus although most of the species were transferred to other genera. Hmmm… 


Isotoma fluviatilis on 8-1-18, #490-4.

I brought this Blue Star Creeper home from Lowe’s on June 10. I had never heard of this plant before, and it looked pretty neat, so I decided to pick out a pot.  

Family: Campanulaceae.
Origin: Australia.
Zones: USDA Zones 5-9 (° F).
Size: 2-3” tall x ? It’s a creeper. 🙂
Spacing: 14” apart.
Light: Full sun to full shade.
Soil: Average.
Water: Average.

The Blue Star Creeper is a neat plant that provides a dense ground cover. Bluestone Perennials says this plant is perfect between stepping stones and is useful planted over bulbs. 

Some websites say it flowers in late spring through early summer and some say it can flower any time of the year…

I read on the Gardening Know How website that the Blue Star Creeper is being used and recommended as a low-maintenance grass substitute for lawns. Isotoma fluviatilis grows no taller than 3” so it never needs mowing, it tolerates heavy foot traffic just like grass, and can be grown in full sun to full shade, even under trees and shrubbery. 

It stands up well in extreme weather but not so well during cold winters and hot summers. Well, the grass is the same way. Mine turns brown in the winter and dries to a crisp in the summer.

The only drawback is it is non-native to the U.S. and in some situations spreads very quickly and can become invasive. But, on the brighter side, they are easily pulled up. 

The Blue Star Creeper is very drought tolerant but appreciates extra water when grown in full sun especially in hot, dry summers. Too much water and fertilizer will make it spread faster.

THEN, I read on Gardenerdy this statement: “A word of caution about this plant, wear gloves while handling it, as it may cause skin irritation or an allergic reaction, due to it being poisonous. Being a non-fussy plant, it definitely deserves a place in every garden.” Hmmm… Are you sure you want to grow it as a lawn substitute if it is poisonous or a skin irritant? 

I didn’t exactly put this plant in an ideal spot and was eventually covered up by the other plants. I kept checking to see if it was still alive and probably should have moved it. It continued to live for quite a while then disappeared. I may try it again if I run across it locally but I will make sure it doesn’t get covered up…

I hope you enjoyed this page and maybe found it useful. If you have any comments, questions or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant.


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