Answer: It's hard to say exactly when you can expect the vine to develop roots - several weeks to several months is average, and depends upon how vigorous a grower the parent plant is. Once roots have developed you can cut the vine from the parent plant, dig it up and transplant it to another location. Sometimes new growth indicates roots have developed, but sometimes it doesn't. Wait until mid-summer, then dig around where you expect roots to be. If none have developed, cover the stem back up and wait another month to check again.
I've found that grapevines root readily, especially if you keep the soil reasonably moist. Hope this information helps!
Q&A Library Searching Tips