Mulch is used to cover pathway to suppress weeds and provide a soft place to work. Mulch is used around the plants and in the pathways to prevent moisture from evaporating from the soil, and also to add nutrients to the soil as it decomposes each year. Check out this great article that explains the pros and cons of using various mulch materials, such as hay vs. straw, rocks, wood chips, etc.
If you bring in straw for mulching or straw-bale gardening, make sure it is organic straw, or the herbicides in the straw may very well kill your plants, and the poison WILL stay in your garden system for many years to come.
Growing Your Own Rootstock
There is a bulletin on it. YoutTube Videos by Kuffel Creek or Stephen Haye’s UK. Kuffel Creek method, but with the stocks in the ground instead of pots. pot with the bottom cut out is a good idea. https://www.youtube.com/watch?v=gn9nzWr9Q1w