Preheat oven to 425 degrees F. In a shallow baking pan combine carrots, celery, onion, and garlic. Drizzle with oil; toss gently to coat. Spread vegetables in a single layer. Roast, uncovered, for 15 to 20 minutes or until vegetables are light brown on the edges, stirring once.
In a large Dutch oven combine roasted vegetables, the water, pork hocks, split peas, savory, and 1/4 teaspoon pepper. Bring to boiling; reduce heat. Simmer, covered, for 45 minutes, stirring occasionally. Remove pork hocks from Dutch oven; set aside.
Stir frozen peas and parsley into mixture in Dutch oven; cool slightly. Transfer vegetable mixture, half at a time, to a food processor or blender. Cover and process or blend until nearly smooth. Return pureed mixture to Dutch oven. Stir in lemon juice.
When pork hocks are cool enough to handle, remove meat from bones, discarding bones. Coarsely shred enough of the meat to measure 3/4 cup; set aside for garnish. Chop the remaining meat. Stir the chopped meat into pureed vegetable mixture. (To serve today, continue cooking until heated through. Omit Steps 5 and 6. Serve as directed in Step 7.)
Transfer soup and the reserved shredded meat to separate airtight containers. Cover and chill for up to 3 days. (Or transfer to separate freezer containers. Seal and freeze for up to 2 months.)
To serve, if frozen, thaw soup and the reserved shredded meat in the refrigerator for 1 to 2 days. Transfer chilled or thawed soup to a large Dutch oven. Cook over medium heat about 25 minutes or until heated through, stirring occasionally.
Season to taste with salt and additional pepper. Garnish each serving with the reserved shredded meat.