[Beachgirl1000]

There are so many edgings you can use that are knitted sideways.

Assuming that the edging is in garter stitch, here's how:
Cast on the number of stitches for the edging plus one more (WS). Knit one row up to the last stitch, and knit it together with one of the live stitches on the edge of the blanket. Turn. Slip the first stitch, knit across.
Next row, begin the edging pattern (RS), knit the last stitch together with the next live stitch of the blanket.
Next row, slip the first stitch, knit across.
Repeat all around the blanket edge.

Note: A relatively narrow edging pattern works best. Here are some to consider---

http://www.ravelry.com/patterns/search#sort=best&query=Lace edging knit sideways

 

[Beachgirl1000]

http://www.ravelry.com/patterns/search#photo=yes&view=captioned_thumbs&query=edging%20knit%20sideways&pa=sideways&pc=edging&sort=created

Beachgirl1000... the link you posted went wonky.... so I used it and came up with the above.....

How odd! Thanks so much for letting me know! Life is wacky enough without wonky links! ????

In the Ravelry pattern search line, I put "Knit lace edging worked sideways" and got 22 pages. Some are rogue patterns, but there are quite a few good ones to choose from.