Slice off the tops and bottoms of the zucchini and slice them in half lengthwise, then cut them in half lengthwise again. They should look like pickle spears. Place them all in a large bowl and coat with 1 1/2 tablespoons olive oil, and 1 teaspoon kosher salt and a few cracks of pepper.
Put the zucchini & squash in a grill basket or grill grid. (If you don’t have either, put them in foil and lightly seal. They won’t get quite the char on them, but they will still be tasty.)
Wash and dry the scapes. Break off the harder, woody ends that don't have the bulb. Using your hands, coat garlic scapes in olive oil and 1 teaspoon kosher salt and a few cracks of black pepper.
Prepare your grill to medium high to heat. Toss scapes directly on the grill and remove them when they’re soft on the inside, crispy on the outside, a lighter shade of green and golden brown in parts. At the same time, place the basket on the grill and cook vegetables on all sides until tender (but not mushy) and slightly charred. Remove from grill and finish with a big squeeze of fresh lemon over all the vegetables, and lightly toss. Taste and adjust salt and pepper if needed.