Blue Star Creeper Care: A Great Ground Cover

Blue star creeper, also known as Isotoma fluviatilis or swamp isotome, is an easy to care for ground cover. Learn to grow it here.

Blue Star Creeper


Are you thinking about ditching your lawn and going with a more exciting ground cover plant? A blue star creeper plant is a tempting lawn alternative, but you might not know exactly how to grow and care for it.

Well, we’ve got the answers to your questions. First thing’s first: blue star creeper is super easy to plant and maintain. Botanically known as Isotoma fluviatilis, it’s a popular cover to work into an ornamental landscape.

Being a low but fast-growing plant, blue star develops into a mass of deep green leaves with delicate creeping stems. They remain evergreen throughout the year.

To learn how to plant blue star creeper and care for it in your landscape, read our complete guide.

Quick Care Guide

Blue Star Creeper
A gorgeous ground cover with blue flowers.Source: KHQ Flower Guide
Common NamesBlue star creeper, Swamp isotome
Scientific NameLaurentia fluviatilis or Isotoma fluviatilis
Height and SpreadShort, 2-15″ tall, and spreads up to 8 feet in 5 years
LightPartial to full sun
WaterEvenly moist soil, weekly watering
FertilizerAll purpose fertilizer once per year
Pests and DiseasesSlugs, snails, damping off, leaf spot

All About Blue Star Creeper

Isotoma fluviatilis is a perennial herb that forms a low-growing mat. It was discovered by Robert Brown in 1810 and was classified as Isotoma by George Bentham in 1864. Blue stars is a ground cover with blue flowers. It’s ideal for planting between paving stones, in the rock garden, or as an alternative for the lawn.

The blue star creeper plant originated in Australia where it grows in riparian areas, or along streams and seepage regions. In the southern hemisphere, it blooms in the summer growing season months of November through March. In the northern hemisphere, it blooms in the growing season from May through July. It spreads via stolons that develop under the earth.

The blue star creeper is very hardy in zones 6 through 8, and can become an issue in certain areas. It’s not classed as invasive, but it gets aggressive at points and can be difficult to remove. It tolerates moderate foot traffic, and therefore can be planted in areas where people will be.

Plant this lovely ground cover in between stepping stones, and in shadier parts of the garden in hot areas. You can also grow it alongside creeks and streams, where it will grow and spread. Be careful not to plant it near slower-growing plants, which it can smother.

Types of Blue Star Creeper

There are three sub-species of the blue star creeper plant you might want to try. They mainly differ in their leaf shapes and sizes.

Isotoma fluviatilis subsp. Australis

This subspecies of blue star creeper has corolla of 7-15 mm long with 5-13 mm long leaves. The width of leaves varies between 2-7 mm. The corolla is mostly blue but you may even find some in pink color.

Isotoma fluviatilis subsp. Borealis

Borealis is more or less the same as Australis which often makes it difficult to distinguish between the two. The corolla for Borealis version of blue star creeper is 6-10 mm long. The leaves are usually 5-12 mm long and 2-5 mm wide. In the flowers, you’ll find approximately 5-40 mm long pedicels. Corolla and lobes are hairy inside and ovary is glabrous in Borealis.

Isotoma fluviatilis subsp. Fluviatilis

This is the most common form of blue star creeper. Its leaves are 5 to 15 mm long and the corolla is glabrous with 4 to 7 mm in length. The female flower of Fluviatilis has 4 to 6 mm long corolla and anthers are pale and small without pollen.

Blue Star Creeper Care

Quick tips on care for this gorgeous cover.

Blue star creepers are gorgeous no matter where you place them: filling the edges of a pond or forming a low, dense mat between stepping stones. It’s also easy to care for – here’s what you need to know.

Light and Temperature

Plant blue star creepers in sunny or partially sunny areas. They need a sufficient amount of light to grow. Full shade is not ideal. If you live in a warmer zone, planting blue star creeper in a location where it has direct sunlight for most of the day will protect your growing blue star creeper.

While it typically prefers a warm climate, blue star creeper can manage to hold its ground in snow cover and temperatures down to -4°F. Heat is not a problem as long as proper irrigation is applied to the soil around your plant.

Water and Humidity

For the best growth, blue star creepers need regular watering. In the first year of growth proper watering is crucial, so that they can firmly establish in the soil. After that, they becomes pretty drought-resistant. However, blue star creeper doesn’t like to sit in water so you’ve got to be careful about where you plant it.

Avoid planting blue star creepers in lower spots that may be susceptible to holding water after rain. Despite their drought-tolerance, you still have to water them well during hot and dry weather to avoid death.


Blue star creepers prefer moist, well-draining soil that doesn’t get too hot in the peak of the day. As a groundcover, it works quite well when interplanted between larger shrubs, bushes, pavers, or trees. Use average garden soil or a good potting mix to amend the existing soil. Ensure drainage is present, and give your blue star creeper a slightly acidic soil for best results.

Blue Star Creeper Fertilizer

Blue star creepers are not heavy feeders, so you don’t even need to fertilize provided you have quality soil. However, an application of a general-purpose garden fertilizer prior to the growing season can help to recondition your soil before planting. Do not fertilize outside the growing season as this can stress your blue star.

Repotting Blue Star Creeper

If growing in containers as an ornamental or houseplant, you can repot it at will. As soon as it starts to outgrow a pot, simply divide it up into smaller pots, or size your pot up by about 1″ or so. This generally occurs once every year or two. You’ll want to up-pot in early spring when new growth begins.

Blue Star Creeper Propagation

If you want to propagate blue star creeper, there are two ways to do it: by dividing the root ball or via seeds.

The root ball can be easily divided by gently scraping the soil from the roots by either using your hand. Split the root ball cleanly with sharp pruning shears and plant it in your desired pot or in the ground.

The second way is rather complicated to carry out. What you need to do is to let the seed pods dry on the plant, then crush them in an air-tight container to collect them. Once you have the seeds, sprinkle them on a moistened seed starting mix.

Once the seeds are evenly distributed on the seed mix, place a newspaper on the container. Make sure to leave a small gap between the container’s top surface and the soil. This will give your blue star creeper seeds a place to sprout.

Keep the container moist and in partial sunlight for 7 to 15 days. When the seedlings reach the six-leaf stage, plant them in the ground or your desired location.

Pruning Blue Star Creeper

Considering the fact that it isn’t native to the United States, it can spread rather quickly, making it aggressive in nature. You will want to prune and shape occasionally to keep the plant tidy.

This fast growth happens when you over-water the plant or apply more fertilizer than necessary. Try using a deep landscape edging material to stop unwanted spreading, or you can hand pull any extra growth easily. Alternatively, if you have a small patch you can deadhead the flowers before the seeds mature.


Swamp Isotome, Isotoma Fluviatilis
This easy to care for cover shouldn’t cause you too many headaches in the garden.Source: Michael Jefferies

So long as you’re keeping blue star creeper well-watered and protected, you shouldn’t have too many growing issues. It rarely gets into trouble with pests or diseases, but it may face some problems if you ignore its growing requirements.

Growing Problems

If you water them too much, the plants will rapidly grow and spread out over the ground. While it might sound good to have a garden full of blue flowers, at some point it will start to take over other areas of the yard or garden that you’d rather dedicate to different plants.

That said, overwatering can also be an issue if you have heavy clay soil that holds on to too much water. You can easily kill the plant by over watering.

Blue star creeper is not an invasive plant by classification, but it can grow in a pattern that resembles an invasive species if you make its growing environment favorable to explosive growth.


You don’t have to be too concerned about pests when it comes to blue star creeper lawn care. The low-spreading plant is not bothered by insects. Also, you won’t have to worry about rabbits making a home in your lawn as it’s resistant to them as well!

However, slugs and snails may snack on blue star creeper in overwatered areas. Either wait for them to come out at night, and hand pick them, or set up a beer trap, where they’ll enter the afterlife drunkenly.


This groundcover with blue flowers is prone to fungal diseases that halt the roots’ ability to grow and develop. So, it’s important that you plant it in locations that are moist but well-drained to prevent nasty fungal issues like damping off and leaf spot.

If you notice either setting in, remove damaged or browning parts. If necessary, replant in an area with better drainage.

Frequently Asked Questions

Q: What fertilizer should I use?

A: Any general-purpose plant fertilizer will be fine. Also, keeping the soil nourished with organic compost can help with growth.

Q: Can I plant blue star creeper in a container?

A: Yes, container growing is a wonderful way to enjoy the beauty of this plant without having it spread all over the place.

Q: How can I control the spread of blue star creeper?

A: If you are planting it as a lawn replacement and want it to stay limited to a specific space, water a bit less often and don’t over-fertilize.

Q: I have dead spots in my ground cover…what’s up?

A: Dead spots can emerge in your swamp isotome cover if the soil is too moist. This can hinder the growth of the root. The second reason could be your soil running out of nutrients. So don’t overwater your lawn and focus on nourishing the soil instead.

Q: Does blue star creeper come back every year?

A: It does. The plant may die back in cold winters, but the stolons will survive and new growth will occur in spring.

Q: Does blue star creeper like sun or shade?

A: It prefers dapple sun to full sun. Some partial shade may be fine for it in areas with well-draining soil.

Q: Is blue star creeper a good ground cover?

A: It’s a great cover that can withstand foot traffic. It also resists deer and rabbits.

Q: How quickly does blue star creeper spread?

A: There’s a reason this plant is considered aggressive. It can spread 18 inches in one year in optimal conditions.

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