Petal sleeves are so much fun. I mean, they look like a flower. No way you can hate that.
Now, if you've got an underarm seam on your petal sleeve, each sleeve will be cut in two pieces. The sleeve we're doing today doesn't have an underarm seam, (we can do that with petal sleeves) so we're working with one piece. (One pattern piece, I mean. Which we'll then use to cut a sleeve and a lining. Don't get all confused on me.)
So, from the petal sleeve pattern, cut 1 of fabric, and 1 of lining:
This sleeve looks lopsided because we've put the overlap, the part that looks like petals, on the front of the arm instead of the top. This way it'll be visible when you're looking at the sleeve from the front.
Make sure you cut your two sleeves out as mirror images of each other, so that they look the same when they're finished, even though they go on opposite arms.
Lining and sleeve right sides together, sew the hem:
Trim the seam, turn the lining to the wrong side, and press the hem, pulling the lining to the inside ever so slightly so that it doesn't show on the right side, thus:
Here it is from the right side.
You'll notice that now the lining pokes out above the sleeve fabric. Fine. We could have solved this already by cutting the lining out using a separate pattern, with a little shave taken off at the hemline, but in my opinion, this is easier. Just so you know it's not a problem with cutting, or drafting, or planning, or you, it's expected and we fix it on the fly. Because we're versatile like that.
Now we'll need to mark the underarm seam (so that we know how to place the sleeve in the armhole) and the overlap line. We'll get those markings from the pattern. The underarm seam is the set of pins on the right here, the overlap line on the left:
Match up the overlap lines on either side of the sleeve, making sure that the sleeve cap also lines up:
And baste along the top of the sleeve cap to hold those two sides together:
Now we'll treat the sleeve as one piece.
If there's fullness in the top of the sleeve, add gathering threads to gather that up:
and now you're ready to set in your sleeve.
Bravo! Petal sleeves!