Here's how to add an RGB LED to a silk flower
Use heat shrink tubing to insulate the leads on the LED. Use different colors of heatshrink so that you can identify the common lead later.
Remove the green plastic core from a silk flower by pushing it out from the back
Push the LED leads through the center of the flower from the front in place of the plastic core.
The LED should be mostly hidden by the petals
Use a small cable tie at the base of the flower to secure the petals and bend the leads out from the center using pliers. The excess cable tie can come in handy for attaching the flower to hair clips etc, so don't cut it off yet.
Use round-nosed pliers to create wire terminal loops for each lead - you can sew onto these loops using conductive thread.
Finished LED flowers ready to include in a wearables project