Ultimately both will make loose heads the size of a large loose leaf lettuce. The plants will regrow new leaves through several cuttings. Both are slow to bolt and tolerate heat and cold, though mibuna is slightly less tolerant of heat. Mature heads are about a foot tall, like a well-grown romaine lettuce. These wonderful salad plants have a texture and bulk similar to romaine lettuce.
Leaves often have a ruffly surface like that of savoy cabbage.
The best salad types have very open heads and are often a pale green fading to yellow at the heart, about the color of bibb lettuce. The outer leaves are slightly hairy, so are not good in salads even if picked young. Not many varieties are available yet. Nichols Garden Nursery offers one called 'Santo', and Johnny's Selected Seeds has one they call 'Lettucy Type'. Compared with heading Asian cabbages, these varieties mature more rapidly, and resist bolting, cold, and disease better.