Peel the carrots and cut into pieces the size of 1 by 2 inch. Peel the parsley roots and cut into pieces the size of 1 by 2 inch. Leek cut into slices about 1 inch thick. Peel the celery and cut into pieces the size of 1 by 2 inch. Wash the potatoes and cut into eighths. Peel the onion and shave it thinly. Arrange the vegetables on the baking sheet, pour over some of the of the canola oil and season the vegetables with salt and pepper. Mix the vegetables well, sprinkle with the herbs, arrange the garlic cloves evenly. Add some water to the pan. Cover the pan tightly with aluminum foil and bake in preheated oven at 200 degrees for 30 minutes. After this time, uncover the vegetables and pour over the blackberry vinegar and bake for another 30 minutes until caramelized. Arrange the roasted vegetables on the plates, add some more oil and vinegar. Add the arugula leaves, herbs and black cumin.