Cut the potatoes in half lengthwise, and place in a medium saucepan.
Cover with water, and bring to a boil over high heat.
When the water is bubbling, lower the heat to a simmer, and cook the potatoes until fork-tender, 10 to 15 minutes.
While the potatoes are cooking, make the dressing by combining the plant mayonnaise, mustard, pepper, salt, and garlic powder (if using) in a small bowl. Mix well.
Drain the potatoes, and let them cool for a few minutes before cutting into bite-size pieces. Place them in a medium bowl, add the vinegar, and toss to coat.
Mix in the celery, green onions, pickles, parsley, dill, tarragon, and dressing.
Chill for at least 30 minutes in the fridge. Then, serve and enjoy!
