Susan is also blogging at GardenRant.Sedum acre / Creeping sedum / Goldmoss stonecrop
It's not for nothing that short sedums are THE predominant green roof plant for roofs without irrigation systems (called "extensive" green roofs, contrasted with "intensive" ones). They arrived in my garden as weeds and in no time at all expanded (with my encouragement) to replace an entire lawn.
The Pollinator Report
Not only do sedums not have to be mowed, but they're covered with little pollinating bees when in bloom (photo below.) Man, what a change from the sterility of turfgrass!
Uses
- In hot, dry spots, on flat land or moderate grades. On steep grades its shallow roots will not hold the soil well enough.
- Among rocks.
- Around larger plants, but not around other short perennials because it would overtake them.
- Edging walkways where it can't overwhelm neighboring plants (see point above).
- Full sun is best in partial shade they still look great, though with taller stems.
Details 
- Blooms gold in late spring, as in the photo to the right.
- To 3 inches high.
- Partially evergreen.
- Very fast spreader
- Suitable in zones 3-8.
- Native to Central Europe.
Care
- Water once or twice after planting and probably never again.
- Poor soils? No problem. Actually preferred.
- Weed around them until they fill out enough to make it impossible for weed seeds to hit the ground and germinate.
- Good drainage is essential (though on my hilly site I've done nothing to improve drainage, relying totally on the grade to prevent wet spots).
- "Propagate" by digging up little chunks of the stuff where it's nice and thick, and sticking them where you want the sedum to fill out. Water a couple of times and repeat as more chunks are needed. Also, stems root on contact with the soil, so if even dropped plant parts will take hold.
Other Creeping Sedums
- Sedum spurium 'Red Carpet' is hardy to Zone 2, vigorous on slopes and flat sites. Similar details and care to S. acre.
- Sedum sexangulare, S. anglicum, and S. lydium are reported to be similar to S. acre (but if you know differently, do let me know.)
Good Information in Print
- Green Roof Plants
by Ed and Lucie Snodgrass, the leading grower of green roof plants in the East.
- Covering Ground
by Barbara W. Ellis - Hardy Succulents
- The Complete Flower Gardener
Not Recommended
- Sedum: Cultivated Stonecrops by Stephenson. I bought this tome and it was waaay too exhaustive (not to mention dry and encyclopedic) to guide me in my plant choices, or anything else.
Sources of Green Roof Plants
- Green Roof Plants is operated by Snodgrasses, who also authored the book of that name. They live and grow in the Baltimore, Maryland area.
- Capitol Green Roofs in the Washington, D.C. area
Location matters
I've grown creeping sedums in the Washington, D.C. area, Zone 7A. If you've grown them in other regions or even near me and had different experiences, drop me a note and I'll add your comments.
Susan