Lori Whit wrote:
I don't want to hijack the thread, but does planting mint actually discourage pests?
In my experience, it does stop rabbits/rodents from girdling the stems by chewing bark (often human or dog hair or even stinky soap will also work at least short term). It did nothing to repulse aphids/ants (wet weather plague) and red spider mite (dry weather) from mineral deficient (iron?) plums. I did not try spraying mint tea, just proximal planting. Spraying the vulnerable leaves might indeed work, but if you are going to that effort, you don't need the plants near each other at all.
True mint (Mentha sp.) is too weedy for most people. Keep it constrained in a tub, periodically harvesting shoots (NO roots/runners) to drape among the branches of things you value, to repulse mammalian pests. Or use similar smelling, less weedy Pycnanthemum (mountain mint). Possibly other members of the mint family would work (ground-hugging, weedy Glechoma hederacea, though I sure smell it, does not) though mint and lemon balm are probably the most (partial) shade tolerant conventional mint family crops. Weedy self-seeding, annual genip/perilla will grow in shade, if you like Korean/Japanese food, though I don't know if it scares bunnies.
It is my understanding that the purpose of daffodils (maybe other Amaryllids in the Deep South) is to repel similar *underground* gnawing damage by things like voles. They sense that it is there, and toxic. But you need a tight ring of bulbs since they aren't smelly and smell probably doesn't travel far in dirt.
-------- other thoughts on the original topic, rather than answering you:----------
BTW, guilds depend on climate. Neither comfrey nor apples do well in FL. Alley crops of prairie acacia might, but perennial Mexican sunflower (Tithonia diversifolia) is the usual "dynamic accumulator"/biomass generator and locally adapted fruit instead of apples. Indigenous legumes, cowpeas where vines are safe, or pigeon peas are more reliable nitrogen fixers (wax myrtle is fine on woodlots but too big and competitive elsewhere) than clover in areas with negligible winters. Many steppe/prairie species (alfalfa, prairie clover; [Petalostemon/Dalea sp.] non-N-fixing Silphium species & big bluestem grass) are also very deep rooted though not necessarily tap rooted. Unless you have clay, I doubt a taproot would matter. In sunny areas with suitable temperature & rainfall patterns, deep rooted N fixers would seem ideal.
For those who think comfrey is edible, beware that pyrrolizidine alkaloids can irreversibly and asymptomatically (until it is too late) harm your liver, though this usually takes chronic use over many years. I've seen studies that show it gets into honey (via pollen; if comfrey is bumblebee pollinated like Mertensia, I wouldn't worry but I am now worried about Echium vulgare), eggs and milk, but not muscle tissue. Therefore comfrey might have value as fodder for short-lived meat animals like domestic rabbits (or cavies if you live in Peru and it is socially acceptable to eat them), assuming that you are like me and can't stomach liver. Comfrey IS good external medicine as well as the fertilizer function.