[flowerpower136]

For a natural edge, I think you've done the right thing. It's exactly what Geoff Hamilton used to do.

The dying grass roots keep the soil in place untill other planting takes hold. Water will leach to some degree especially in very dry weather, but it's the best method I've found to achieve a natural edging and completely hide the liner. And when planting covers it, the leaching seem to lessen, I suppose the ground cover that the plants provide, shades the soil and stops it drying out so fast.

If you plant low to medium size spreading bog plants, eg Myosotis, you won't have any problem with roots, they'll knit the soil together but won't harm the liner. Just avoid anything tall that needs deep roots to anchor itself, eg Iris pseudacorus. That's a plant that is capable of piercing liners, though even then, the root itself will act as a plug and keep the water in. It only becomes a leak if the plant dies and the root shrinks.

Hope you have many happy hours of pond watching.