Beyond curb appeal, a good layer of mulch helps beds retain moisture between waterings, suppresses weed growth by blocking sunlight, and moderates soil temperature for plant roots.
Hardwood mulch breaks down over time and adds organic matter back into the soil, making it a solid all-around choice for most garden beds. Dyed mulches hold their color longer through the season, which matters if curb appeal is a priority. Lighter materials like straw or pine needles work well around more delicate plantings.
A fresh 2-3 inch layer is usually the sweet spot — too thin and it won't suppress weeds effectively, too thick and it can actually hold too much moisture against plant stems.
Most beds benefit from a fresh top-up once a year, typically in spring before the growing season kicks into gear.