I know this seems complicated but I use Herringbone Stitch for all my hems. I first got taught this technique when I was working at the- now sadly closed down & sold off for parts- BBC Costume Department in West London.
The reason it was being used on costumes was twofold… firstly it doesn’t show from the front, at all! Secondly, it’s super strong. If your heel gets caught & rips one stitch the rest don’t immediately unravel because of the way Herringbone Stitch is worked.
Herringbone stitch, often called Catch Stitch, is a most useful little stitch to know. As you can see from the above diagrams, it is a version of Back Stitch, in Cross Stitch form. Turn your hem up as needed, or refer to your pattern for instruction.
Firstly, thread you needle in a complimentary colour, then stitch a couple stitches ‘on the spot’ to start. This stitch is worked backwards so the first stitch you take will be through the main body of the fabric. Take a stitch from right to left but only take up a couple of threads of the fabric. This stitch should lie directly above the hem fold as illustrated.
Secondly, and roughly 1.5cm to the right of the first stitch, take a larger stitch through the fold in the fabric. Do not go all of the way through to the front. Move to the right again and take another stitch through the main body of the fabric, as illustrated, and only taking up a couple threads. Continue until the hem is complete or you need to re-thread.
The examples above I have completed in black & white, so you can imagine how the stitches disappear when executed in a complementary colour.