spring greens 
plural noun
The leaves of young cabbage plants of a variety that does not develop a heart.You could use cavolo nero, Swiss chard, kale, sprout tops, spring greens or Savoy cabbage, listed in my order of preference....
- Leafy dark green vegetables, such as Savoy cabbage, kale, and spring greens, are good sources of two carotenoids which have been shown to help prevent age-related macular degeneration and cataracts.
- Serve with tagliatelle and, if you like, other vegetables such as spring greens or spinach.