Groundcover Warning: Blue Star Creeper, Pratia pedunculata, Laurentia fluviatils, Isotoma fluviatilis

Blue Star Creeper, pretty flowers, pretty aggressive, pretty finicky about growing conditions, etc.

Blue Star Creeper, a.k.a. Pratia pedunculata, Laurentia fluviatilis or Isotoma fluviatilis

Pros:

- Spreads fairly quickly. Tiny plants 2-3 square inches can form an expanding patch 10-15 feet wide within 2-3 years.

- Profusion of charming light blue flowers in spring for several weeks. Bloomed starting mid-May this year and was still covered in flowers in early June. In cool summer climates, Blue Star Creeper might bloom all summer. I say that because our temperatures have been cooler than average most of this summer (highs in the mid-80s or lower many days) and Blue Star Creeper started reblooming in late July. The flowers do seem to attract some small bees, wasps and/or hoverflies.

- In spring, the foliage can make a lush green carpet.

- Tough. Survives heat, cold, drought and wet conditions (though it may not look good in the process).


Cons:

I ripped up a patch of Blue Star Creeper here a couple of weeks ago. Clearly I did not get it all, because bits and pieces are creeping back. Gonna have to try to dig it out again. Could take a few tries (at least) to eradicate Blue Star Creeper from a garden bed.

- Hard to control. Blue Star Creeper spreads on below-ground rhizomes. And it tends to travel a little...unpredictably, not necessarily advancing in a straight line, but suddenly popping up several feet away. When I decided that Blue Star Creeper was insinuating itself where I did not want it, I started digging with my Cobra weeder and found that Blue Star Creeper had made a thick web of white roots below the surface (see photo below). When you try to uproot this Creeper, the roots are likely to break, leaving bits and pieces below ground to resprout. This extensive underground root system makes controlling or eradicating Blue Star Creeper a challenging proposition - at least through manual means. (I have not tried spraying it with any herbicide because I tend to avoid using such chemicals when possible.) Since the plant grows so close to the ground and the leaves are so small, that also makes it hard to get a grip to pull up a patch. The fact that Blue Star Creeper is an invasive exotic is another strike against it since we can't count on co-evolved predators or pathogens to keep it under control. That being said, at least Blue Star Creeper is diminutive. Generally it only grows a few inches tall, so at least it's not about to climb and strangle a tree as kudzu might.

These roots are just a small representative sample of the web that Blue Star Creeper has woven underneath the soil. It's pretty scary stuff. My advice -- stay far, far away. I imagine I'll be fighting to get rid of this for years to come. I wouldn't mind having a small patch, but I don't think that's possible unless I wanted to grow Blue Star Creeper in a pot.

- Not native to the U.S. The nomenclature is very confusing on Blue Star Creeper, but according to Paghat, there are actually two different species that are frequently marketed under the same common name, one from Australia and one from New Zealand.

- Doesn't block weeds all that well. Blue Star Creeper's small size may be an asset in terms of making it not-that-thuggish, but it also makes it only partially effective as a weed-blocker. So it's kind of a lose-lose situation - the Blue Star Creeper insinuates itself like a weed, but it's not actually thick or tall enough to shade out other weeds like clover. And as Paghat says, "some weeds are practically nursed by the mat of [Blue Star Creeper] foliage, and weeding will mean ripping out big patches of the ...creeper."

- It just doesn't look that good much of the year. Heat and cold and drought and wetness may not kill it, but they can make it look like Hell warmed over. More specifically, in cold weather, the plant may brown and sort of disappear under the soil. In hot weather (especially in full Tennessee sun) the plant may bake to a crisp and disappear. In drought, you guessed it, Blue Star Creeper pulls a disappearing act. That's sort of a pity, because if the plant were green and mat-forming all year, at least I could consider using it as a lawn alternative (assuming that deep metal or plastic edging could control its spread...which I don't know for sure). It's so low-growing that at least it never needs mowing!


Conclusion:

To sum up, Blue Star Creeper is aggressive, invasive (in the U.S.), offers poor weed suppression and has low aesthetic appeal for much of the year. I can't recommend Blue Star Creeper for the Southeast and I certainly would urge caution before adding it to your garden. Read some of the other negative experiences that Dave's Garden reviewers have had. Blue Star Creeper is one of the few plants that I regret planting. I'm now trying to undo that mistake and warn others from making the same error.

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