Why not grow a plant that produces veggie spears with a plant that also produces veggie spears? Asparagus plants are also very moisture loving, fast-growing plants so choose a planting site that retains a lot of moisture, gets a lot of rain run-off from the roof of your house, and contains a lot of humus and top soil to allow both the asparagus plants and the hostas to put down plenty of deep roots to keep them growing at top speed.
Though asparagus does cast some shade once it has filled in, it certainly would not be enough to keep sun-sensitive hosta plants from being baked by a hot summer sun. You can counter this by companion planting two rows of asparagus plants and allowing the hostas to spread between them, giving them dappled sunlight and high humidity.
More tips on how to grow asparagus.