Stalks and stems on leafy green vegetables generally contain the same nutrients as the leafy part itself. Crushing or cutting the stalks and stems will not change the nutrient profile in any significant way.
Leafy greens are packed with vitamins, minerals and fiber. The stalks and stems on leafy greens are completely edible and can add a nice crunch when eaten raw. If salad is not your thing, try experimenting with different preparations for leafy greens. Use greens to top a pizza or toss spinach into a frittata. Romaine lettuce can be grilled for a whole new flavor combination or you can use it as a wrap instead of a tortilla. The possibilities are endless.