I live north of San Francisco, in Sonoma County. I have found a good tree in a field that I would like to collect. I believe it is a valley oak. My question is if it is already too late into spring to dig this tree up? Today is May 19th. The tree has just begun sprouting new growth
I’ve collected three coast live oaks before, so hopefully someone with more experience can chime in. I’m not sure how different collecting Oaks compared with other types of trees is. However In general, I think early spring before a tree has a big push of growth is the best time to collect. Fall is also a good time. For Sonoma county area, and because you said it already has new growth makes it a little past the ideal time to transplant. However, I’ve collected trees with success at many different times of the year. If I thought I could get a good root ball, I don’t see why you could not collect now. If you wanted to be really safe, I might wait until spring or fall. Good luck!
I can’t speak for your region, but the oaks here have deep deep tap roots and are poor for collecting. That said I am experimenting with earth layering them ( wrapping wire on the tap root 8" down, adding root hormone and peat or coco earth) and collecting in a couple years. Most deciduous trees here (Winnipeg, Canada) need this treatment, excluding my favorite alley trees that grow in pots of lazy (unsweeped leaves).