Cedar

i don't see how a darker color would look less like a hole than a lighter one. If anything a darker color is more likely to recede than a lighter one. For the center star I would use something with at least as much contrast with your rust color as the purple, the purple is close in value to your rust (if a black and white photo were taken the star would be hard to see) but it works because the purple and the muted yellow/orange of the brown are so different in color.

The rule I was given in color theory is that colors are divided into three parts: color (red, yellow, blue, orange, green, and purple. Brown and grey are just variations of these. Your brown and grey fabric is muted orange and blue. White and black are extremes used only for total lack of the main colors -- white is white, but cream is yellow), value (if the would were black and white would it be lighter or darker), or chroma (the brightness vs mutedness of the color -- robin egg blue vs steel grey). If you match just one of these areas your colors will match. It's a rule from a teacher we called the art natzi and doesn't always work but its a useful way to figure out why something is or isn't working.