Autumn olive / Elaeagnus umbellata

Autumn olive is vigorous and starts fruiting within three years, sometimes sooner. The small speckled berries are tart-sweet and very high in lycopene. It fixes its own nitrogen so thrives in poor soil without feeding. Be aware this species is considered invasive in parts of North America, so check local regulations before planting. You will get better crops with two plants for cross-pollination, though some cultivars set fruit alone.