Blue Star Creeper Plant Profile

This pretty ground cover plant is the perfect grass substitute

Close up picture of blue star creeper (Isotoma fluviatilis) light blue flowers.

David Stang / Wikimedia Commons / CC BY-SA 4.0​

Looking for a low maintenance grass substitute? Alternative ground cover lawns are increasing in popularity and blue star creeper is the perfect grass substitute if you are looking to switch up the look of your lawn. Blue star creeper has a spreading and mounding growth habit, forming a dense, low mat of leafy green foliage. In the spring and summer months, blue star creeper is adorned with delicate pale purple to blue star-shaped flowers. It requires less water than a traditional grass lawn, and since it only grows to be three inches tall you can get rid of the lawnmower, because mowing is not necessary! Notorious for being a hardy plant, this Australia native can tolerate heavy foot traffic, extreme weather conditions, and even drought. Besides being a viable grass substitute, blue star creeper can also be used as a filler between patio stones, cover for spring bulbs, or as a border plant.

Botanical Name Isotoma fluviatilis
Common Name Blue Star Creeper, Swamp Isotome
Plant Type Herbaceous perennial
Mature Size 3 inches high, 18 inch spread
Sun Exposure Full sun
Soil Type Moist, well-draining
Soil pH 6.1 - 7.8
Bloom Time Spring, summer
Flower Color Light blue, light purple
Hardiness Zones 6 - 9
Native Area Australia, New Zealand

How to Grow Blue Star Creeper

Blue star creeper (Isotoma fluviatilis) is a herbaceous perennial in the Campanulaceae (or bluebell) family that is native to eastern Australia. It is characterized by short, dark green foliage and delicate, pale blue to purple flowers that grow upwards on slender stalks. Blue star creeper is an easy plant to grow, requiring little ongoing maintenance once established. It grows in a spreading and mounding habit reaching a maximum height of three to five inches, which makes it an excellent no-mow ground cover choice for residential lawns and gardens. Plant individual blue star creeper plants at least eight to 10 inches apart for thick coverage. 

While blue star creepers are not invasive by definition, they are not native to the United States and can spread quickly, becoming invasive in some situations. Keep this in mind when deciding where you’d like to plant blue star creeper. It can be easily contained with deep garden barriers or walls. 

Light

For full, colorful growth, blue star creeper should receive direct sunlight for most of the day. If necessary, blue star creeper can adapt to part sun but the growth may not be as dense.

Soil

Blue star creeper is not picky when it comes to soil. As long as it is planted in a moist, well-draining medium it will be happy. The soil should have a pH level between 6.1 to 7.8, or mildly acidic to alkaline.

Water

Blue star creeper can be described as having medium water needs. It is known for being drought tolerant but thrives with adequate moisture in the summer months. During the summer, keep the soil moist with regular watering to support strong growth.

Temperature and Humidity

Blue star creeper is a resilient, cold-hardy plant that can withstand temperatures as low as -4 degrees Fahrenheit (or -20 degrees Celsius) with snow cover. However, it thrives in the warmer seasons and requires warm spring and summer temperatures in order to survive. While the growing season varies, blue star creeper usually blooms from spring to late fall. It is hardy in USDA zones 6 through 9. 

Fertilizer

Heavy fertilization is not required for blue star creeper. In fact, fertilizing blue star creeper too often can encourage aggressive growth which often becomes invasive. Fertilizing once at the beginning of the growing season with an all-purpose fertilizer will help to encourage strong new growth. 

Pruning Blue Star Creeper

Shearing the foliage of a blue star creeper to about one inch tall in the late fall will help to keep the plant tidy throughout the winter and in the spring as new growth emerges. Other than this optional upkeep, blue star creeper is a low-maintenance perennial that does not require deadheading - flowering throughout the spring and summer continuously without assistance.

Propagating Blue Star Creeper

Blue star creeper is readily propagated by seed and by division. Blue star creeper spreads by rhizomes that grow both above-ground and below-ground, which means that plants can be easily divided and transplanted. When dividing blue star creeper, carefully dig around the rhizomes and root ball, preserving as many roots as possible. Gently separate plants from one another, and plant immediately. 

Varieties of Blue Star Creeper

Blue star creeper is native to Australia and New Zealand and has many different varieties. The different varieties of blue star creeper mainly vary in their leaf sizes and shapes. The most popular species include:

  • Isotoma fluviatilis subsp. Australis has a corolla of 7 to 15 millimeters long with 5-15 millimeters long leaves. 
  • Isotoma fluviatilis subsp. Borealis has a corolla of 6 to 10 millimeters long and looks very similar to Australis which sometimes makes it hard to tell between the two. Long pedicels in the flowers of Borealis are a distinguishing feature.
  • Isotoma fluviatilis subsp. Fluviatilis is the most common variety of blue star creeper. Its leaves are 5 to 15 centimeters long and the corolla is 4 to 7 millimeters in length.

Growing From Seed

Blue star creeper seeds can be harvested from mature plants, or purchased at a nursery or garden center. Sow the seeds on moistened seed starter mix and cover the container with newspaper. Keep the container in a location where it receives partial sunlight, and keep the soil consistently moist until the seeds sprout. Blue star creeper seeds take anywhere from 7 to 15 days to sprout so be patient!