Sprinkle beef evenly with salt and pepper; dredge in flour.
Heat a large skillet over medium-high heat.
Add oil to pan; swirl to coat.
Add beef; saut 10 minutes, turning to brown on all sides.
Place turnip greens in a 6-quart electric slow cooker; top with parsnips, potatoes, and onions.
Transfer beef to slow cooker.
Add tomato paste to skillet; cook 30 seconds, stirring constantly. Stir in wine and broth; bring to a boil, scraping pan to loosen browned bits. Cook 1 minute, stirring constantly.
Pour broth mixture into slow cooker.
Place peppercorns and next 4 ingredients (through parsley) on a double layer of cheesecloth. Gather edges of cheesecloth together; secure with twine.
Add cheesecloth bundle to slow cooker. Cover and cook on LOW 8 hours or until beef and vegetables are tender. Discard cheesecloth bundle.