Very hardy lettuce with tall light green leaves with pointy tips and a pronounced ribbed structure. It combines the crisp texture of an icicle lettuce with the hardiness of some of the older lettuce varieties such as Oak Leaf.

Cos does not hold for long in the ground as it tends to go to seed after a fairly short space of time.  It also does not have quite as fine a texture as an icicle lettuce Such as Great Lakes.  However it is far hardier as it is less susceptible to slug and snail damage and does not get the disease  Downy mildew  , which regularly strikes icicle lettuces.

Cos makes a good substitute to icicle lettuces.  Especially in the warmer weather when Downey Mildew is likely to be more active.