what do you plant in marginal spaces?
I often have marginal spots that I'd like to fill with some kind of useful plant, but those spots often just wind up growing junk because I don't know what to put in them. Mainly these spots are marginal because they don't get full sun and they have large trees to compete with nearby. All these spots would get direct sun for at least two or three hours per day, though. Are there edible (or other useful plants) you'd recommend for spots like these? Here's what I'm looking for:
1. something that won't sacrifice quality (especially sweetness if it's a fruit) even if it doesn't do as well as it would do in a better spot
2. something that's cheap and easy to propagate; if it takes very much time or really any money I'm going to invest that time/money in a better location
3. something that will produce something even in this marginal spot
4. if I haven't already ruled everything out, something that isn't highly attractive to squirrels, because being next to big trees generally means lots of squirrel pressure
Pawpaws seem like they might score well enough on points 1, 3, and 4, but not so well on point 2. Would tame, thorny blackberries lose fruit quality? Maybe I could grow pollinators like male kiwis or muscadines in these kind of spots. What do you all do? Any recommendations? Thoughts?