I plant daylength sensitive south american tubers between garlic because they don’t really start to take off until well after the garlic has been harvested. The oca and ullucu can go in anytime after the final frost and once the soil has warmed up a bit, as long as the garlic has been well weeded first. So not the early stages, but well before the last stages. The period of drought that garlic requires before harvesting doesn’t seem to hold them back too much.