I agree with the other ladies, make the seams flat, but remember you are dealing with bias and it will stretch if you are not careful to press not scrub on those seams while flattening them. Also, the fabric could be your problem. Use a good quality soft fabric. It your fabric is as stiff as a board before you begin, that is the wrong choice. While making your seam, take the true bias path to sew on. If you get off, it does make a difference when you turn it around to use it.

I hope some of this rings a bell and helps a little.

I really should have asked first instead of getting all excited and just going for it. Perhaps careful leaf placement is my solution if I want to continue with my bias tape.
The pattern calls for a 3/8" bias strip to be stitched down on the wrong side and then finger pressed in to the stitch line. Which is what some of you do. I thought that I would struggle with keeping it even and wanted to be able to focus on my hand stitching (not beautiful yet) so I made 1/4" bias tape. Maybe I should try your way before I decide that it's too hard to do.
The bias bars look wonderful and I will definitely pick up a set at my LQS next visit. Thank you for pointing them out.
The runner is 40" long with a stem running up the middle so there was no way to avoid a seam. I did press it open. It is just a lot of fabric in so skinny a strip.
And yes, I tried stitching a few pieces down before I got going and I am very surprised at how much I am enjoying the hand work. It will be so nice to have something to take with me and to sit outside with in the nice weather.
Thank you for all the ideas. I will see which way I can have the best success with.

Buy a singer bias tape maker it's the best ever to make steams.it is electric and works great

I don't understand having a joining seam in the applique stem. Why not cut the length you need from the length with no connecting seam? I'd cut the seam connection out of the length and toss it.

You can absolutely make a 40" long stem with no seams. A 1 yard cut of fabric will give you a 44" long bias strip. Yes, you will have lots of leftover fabric, but that's what stashes are for, right? You can use the extra for leaves. :)

That's how I would do it, but that's just me.

Try using bias bars. I have tried all methods and really like the bars the best. By using the bias bars, my stems come out beautifully. Welcome to the world of hand applique. I just love it and find it very relaxing. Have fun.

Hey, just curius, if Im having success with my stems the Clover 1/4" bias tape maker, should I be worried the raw edges may become exposed when I wash the quilt? Perhaps the key to my success is a tip I learned to spray starch on them before I iron. In any case, I have the bars, but this is so much faster and easier. When using the bars I need more fabric, struggled with sewing the width correct and the raw edges peeked out anyway, so what am I missing?