Forage Collards have a deep growing taproot and will not form a tuber or a bulb, but rather they put their growth and energy into producing very large and nutritious leaves. This is an important characteristic. When plants start developing their reproductive system (seeds, tubers etc.) they tend to slow their leaf production but Collards have a much longer vegetative (growing) period. IF you plant collards in the fall and leave them overwinter they will move into the reproductive stage. Forage Collards have demonstrated the ability to stay green into December, even after temperatures had dropped below 0° F.
The deep taproot that Collards form tend to help drill into compacted soils, helping to breakup the hardpan. They are good nutrient scavengers utilizing excess nutrients left from other crops.