Roser is the Catalan word for "rose bush" — also the Marian title Mare de Déu del Roser (Mother of God of the Rosary).
Roser is widely used in Catalonia.
Roser does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Roser reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.