So this is a question about remedying a severe case of procrastination. :)

About 25 years ago, the father of a good friend, a ‘tinkerer’ in the garden and orchard, gave me 3 young hazelnut plants to put in the yard of my new home. He said they were “crosses” he had done himself, and that I needed at least 2 to get cross pollination to get nuts. I thought maybe he meant crosses between filberts and hazelnuts? I did not and do not know much about the difference between these. He had several big hazelnuts growing in his yard, which I got to try, and they gave nuts about 1/2 - 3/4 the size of standard store-bought filberts. Unfortunately two of the three plants died in the first two years, and as I was extremely busy with work and a young family I just let the other grow. My friend’s father started with dementia a couple years after the gift to me, and I could not get more info on what he was growing.

Well, now I have a huge 15 foot high, 12 foot wide bush now that gets covered with ‘catkins’, but has never produced nuts (no pollinator, I know). The question is, should I try to graft a couple of other types to some of the branches, or plant some other types nearby? And what types of hazelnuts do you suggest I should use? I have little experience grafting, and have never tried with hazelnuts, obviously