Up until now I've just been mulching around my apple trees. But I've decided it's time to get serious about making an apple guild.
"Guild" is a permaculture term that means a group of plants, usually with a food-bearing tree in the middle, that support each other, providing for each other's needs. They typically consist of some combination of nitrogen fixers (so you don't have to fertilize so much), deep-rooted nutrient accumulators (for bringing nutrients from deep in the soil up to where other plants, including the tree, can use them), insect attractors (for attracting pollinizing and pest-eating insects), mulch makers (than you can slash periodically for on-the-spot mulch, or that drop a lot of litter to act as mulch), and ground covers (to protect the soil from splashing rains and too much sun, and to suppress weeds). Typically, some of the plants will be shrubs and some will be perennials. There may even be a vine or two. Annuals are usually avoided in a guild, unless they self-sow.
I'm just starting this guild, so it doesn't have everything it will eventually have. For example, I'll want to put 4 or 5 berry bushes around the edges--maybe goosberries, currents, honey berries, or goumis (which are nitrogen fixers). And I don't have any nitrogen fixers, but I bought a packet of sweet peas, which I'll plant to grow up the cheap-and-cheesy deer fence.
So here's what I got, and why I got it.