Vinca is tough enough to not mind being yanked aside while you deal with the bulbs.

I agree with floral_uk. I have bulbs growing in vinca, and it's easy either to work my shovel through the vinca, or if some of the vinca needs to be dug up to transplant it elsewhere.

Thanks floral and eaga-that is promising, as I love the flowers. One more question, do you find the roots run deep like euonymus vine? I had to dig that out and it was a nightmare! Just want to know, whether you thought this of your established vinca. If the roots are shallow, then digging won't bother me.

In my experience, the roots of my vinca are about 3-4" deep. I recently moved quite a bit out of one bed and into another, and found it came up easily - I just sliced down through it with a digging fork. The roots didn't go as deep as some of the daffodil bulbs that were growing in it. My garden has pretty loose soil, sandy loam mostly, so your experience might be different if you have harder soil.

You might experiment by digging up a small piece and examining the roots, to see if you would be comfortable maintaining it longer term.