I harvested some elephant garlic earlier this month, big fat bulbs with good clove differentiation. I pulled out some smaller ones today as their leaves were withering and the stems had fallen over. These have monobulbs, as sometimes happens with elephant garlic, but the monobulbs are still good for cooking or resowing.
Why do monobulbs form? It’s usually explained as the season being too short but it doesn’t seem to be the case here. All were planted in Autumn in the same, open, sunny bed without competition from weeds or other plants.
I think the little dark bulbs are a way of the plants propagating themselves more widely.
Plant one in autumn and you get a larger, one clove garlic.
Plant that in autumn and you get an elephant garlic.