When it comes to boutonnières, there are tons of options so I’d like to offer some guidance and suggestions. In many ways, your attire can help dictate your boutonnière. If you’re wearing a tux (the most formal option) I would recommend a very elegant and chic boutonnière, often a large focal flower with some greenery. If you have a button-down shirt with suspenders, you’ll want a more minimal, dainty boutonnière since the suspenders will need to support its weight.
If you’re wearing a suit jacket, you can go with something larger and more fun and unique: anything from a single large rose to an elaborate cluster of flowers and textures from the day. You can even throw in interesting elements like feathers, a bullet casing, a wine cork, or go with an herbal-based boutonnière (sage, basil, thyme ect.) or even succulents. For all of these boutonnière options, you can choose to go with all greens or neutrals or incorporate as much color as you would like.
Note: For men who are wearing a more causal shirt (a button-down with no jacket or suspenders) you can pin something super lightweight like a small, textural cluster, but understand that this is not ideal and may create folds and weird creases in your shirt. In this case, I often recommend skipping a boutonnière.