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American stem celery is not that leafy, but Asian varieties have narrow stems and are all leafy bush. It's used as an herb like cilantro, and you can use the American stuff the same way if the leaves are still looking good. European varieties too, but they're typically grown for the big root (celeriac).
The tops of beets are also soft and nice, kind of like spinach but with a big stem that's kind of like a celery stalk. Varieties with a large top for this usage are very popular now, you may know it as "Swiss chard." The commercial reality of vegetables doesn't always reflect their anatomy, and as a grower you may be getting three or four tasty ingredients from one plant.