The celery does not develop bulbs. The bleached ones are made by him, delicate leaf stalks used as vegetables.
A distinction is made between varieties with white to yellowish petioles and light green leaves, which by nature already look «bleached», and varieties with dark green, partly reddish or violet striped petioles. The latter usually mature later, bring higher yields and must be bleached, while this is not necessary with the so-called "self-bleaching" varieties. The health value is similar to that of celeriac. Blue celery can be used very well for the production of spicy raw vegetable salads. You can also steam it and prepare it like celeriac. In any case, it is very appetizing.