Prepare the eggs by placing them in a large pot and covering with cold water by 1 inch. Bring to a boil, then immediately remove from heat, cover, and let stand for 12 minutes.
Transfer eggs to an ice bath and cool completely before peeling to ensure easy removal of shells. This prevents those frustrating tears in the egg whites that can ruin presentation.
Slice each egg in half lengthwise and carefully remove the yolks, placing them in a medium bowl. Set the white halves on a paper towel, cut-side down, to drain excess moisture.
Mash the egg yolks thoroughly with a fork until no large chunks remain. A smooth filling is crucial for piping detailed tree shapes.
Add mayonnaise, herbs, mustard, lemon juice, garlic powder, salt, and pepper to the yolks and mix until completely smooth and vibrant green. If the mixture seems too thick, add a touch more mayonnaise.
Transfer the filling to a piping bag fitted with a medium star tip. The star tip is essential for creating the textured “pine needle” effect of the trees.
Place the egg white halves on your serving platter, arranging them in a tree formation if desired (larger ones at the bottom, smaller at the top).
Pipe the filling into each egg white half in a zigzag motion from bottom to top, creating a tree shape. Start with a wider base and gradually narrow toward the top.
Decorate your trees by placing small pieces of red bell pepper or pimentos as “ornaments” and a tiny piece of yellow bell pepper or shredded cheese at the top as a “star.”
For an extra touch, insert half a pretzel stick into the bottom of each egg to create a “tree trunk” effect.
Refrigerate for at least 30 minutes before serving to allow flavors to meld and the filling to set slightly.