If the 10 in your reply refers to USDA zone 10 conditions, then there are 100's of groundcovers you could use in the gaps between concrete pads with drip irrigation. I am assuming you used in-line emitters with 12" or 6" o.c. spacing or soaker line. I would suggest things like Isotoma fluviatilis, Baby Tears, Dymondia(best with more sun and let somewhat dry in between irrigations),Dwarf Mondo Grass, Irish or Scotch Moss, Australian Violet, etc, etc. I hope that you have this area valved separately from the other drip within the garden, because in such a limited space you don't need more than just a few minutes daily to keep it well watered, and if it is drip connected to other drip areas, you are probably watering much longer than that. You might also consider using mexican pebble laid on edge and mortared in place as an alternative to ground cover, as almost any ground cover will eventually require clipping and grooming to keep it neat, which I suppose was your reason to remove the grass. If you do want to explore the grass look alike options, Carex pansa or Zoysia grass would also be good options, and require less clipping on a weekly basis than fescue or other cool season grasses.

Those that suggested "it might work"...evidently don't have a lawn and no nothing about drainage. The reason there's lawns in front of homes is because there's soil under them and water drains away after the grass takes what it can use. Since there is no possible way concrete or rubber, or plastic, or anything else that you try to substitute to rid the place of water, then there's no way to grow grass on them. If you want a lawn, then commit yourself...break the concrete up, remove it, and replace with good soil. Then use either sod or seed. If you wish to not remove the concrete, might I suggest you invest in a look-a-like grass---much like they use on baseball fields. It looks real, can be cut to measure and you wont need to buy another seed of grass...ever. There is only the problem of cost....it does cost a prety penny....and an even duller dollar. There's many dealers in this product so choose wisely.

do your neighbors have subsurface drip irrigation systems? Apparently, with SDI, if you do rototill in amendments, make sure to re-compact the soil nice and firm afterwards. If the soil is too loose and well draining, the SDI system might not work very well. Check out this link, about a third of the way down the page: http://www.jstryker.com/goofing/houselandscape/index.htm quote: "subsurface system on the lawn has been a disappointment. My lawn has had numerous dry spots that developed shortly after the sod was installed, and I have been unable to eliminate them by adjusting the water run times... I had used a similar product on commercial systems several years ago with success, so the problem is specific to my situation. It appears the problem is due to a combination of porous soil and insufficient soil compaction. The idea of the subsurface drip is that the water comes out of the emitters (holes) on the tubes and then it moves through the soil, by capillary action, up and sideways to wet the entire area. However the soil in my yard is very porous and was dug up to remove roots, so it was very loose. As previously noted we rototilled the soil to remix it and put a lot of organic amendments into it. After we aerated the soil we then compacted it to industry standards using a water-filled roller. We then installed the sod and compacted it again using the weighted roller. Unfortunately, while this is the normal procedure for installation of a new lawn, this apparently was not sufficient on our very porous soil to create enough contact between the soil particles to allow the water to move by capillary action.... ....the water is going straight down in the soil and only wetting the area directly below the tubes. I believe this is because the soil needs to be compacted a lot more firmly when using the subsurface system than occurs when using the standard weighted roller compaction method I used.... The lesson learned is that the subsurface drip system does not work well in porous, well-draining soils, and if it is to be used in a well drained soil it is important to over-compact the soil.... ....If your soil is less porous, then the subsurface drip system can work well. I have used it successfully on lawns in several locations, but in all those cases the soil was compacted using heavy tractor mounted compaction equipment."

I have what I think is the same aggregate for my driveway (1969 home). I am thinking about getting stamped concrete put directly on top of my existing driveway. They use an abrasive cleanser, then pour a thin layer of concrete over the existing, make designs with a trowel or rubber stamp and then stain it. It is a great option, especially if you want to set chairs on the patio and don't like to rock from the uneven flagstone. If you do it yourself, careful with the stain, it is a one shot deal and my wife wishes I would have found that out before I did our front porch. -joe