Different varieties have different flavours. You can shake the tree to see if they are ready. You leave them in the husk and let them rot with the husk on. The bitterness of the shell goes into the nut so the best thing to do is to clean them when they’re green turning yellow and get that off. To get the husk off, I step on them on something hard like concrete and roll them under my feet. I then throw them in water and stir them up so they clean each other so the nuts are rubbing against each other then pour the water off until they are relatively clean, let them dry then let them sit for a month because the nut inside is not ready then I crack them with a nut cracker. If you use them right away they are too moist – there’s too much water compared to oils. They have one in the Christchurch Botanic Garden and it was called California Black Walnut. We call them Heart Nuts because they are heart shaped. The Heart Nut Juglans ailantifolia has a smooth shell whereas the Black Walnut Juglans nigra has a sharper shell. Ref: Rob Danford – NZ.