Hello Calliope, welcome to Using English!
I would hyphenate where both components are vital to the adjectival notion, e.g.
1. A smoky-voiced chanteuse.
2. A primrose-yellow tie.
3. A narrow-leaved geranium.
But I wouldn't hyphenate where the first component modifies the degree, rather than the nature, of the second component:
4. A pale yellow tie.
Or where the first component is an adverb:
5. A beautifully stitched handbag.
Opinions on hyphens vary greatly, though, so other members may think differently!
All the best,