Then I would ask the orchard owner to investigate "plant guilds" that work with his/her crop. These supportive plants at the base of the trees can provide more nutritious, longer periods of forage for bees.
Permaculture fruit tree guilds are mini-ecosystems that reduce predatory insects and disease. Any monoculture has weaknesses (for example, the Irish potato famine). Biodiversity reduces risk, even if it is not a cash crop like the fruit. Legumes like clover can add nitrogen for the fruit's use. Then the bees can forage on the clover (however some clovers work for butterflies but not bees). Periodic mowing of certain fruit guilds can bring re-flowering for bee forage, and add green mulch to the soil.
Guild plants:
Must thrive - proliferate, grow without support, self-sow freely, or expand through rhizomes or stolons. What may be invasive in a suburban garden is very useful on 50 acres.
Be good for trees - pest-repellent, fertilizing or anti-fungal. For example, garlic at the drip edge of apple trees can reduce fungal scabbing, but it won't expand fast enough to block noxious weeds. And too much crowding isn't good if fungal issues are always a threat, so choose low-growers.
Be good for bees - Such as early crocus, or mints that bloom into late fall. But if crocus can't take heat in your location, it won't thrive and naturalize.
So the plants have to meet all criteria.