As-Salamu Alaykum wa Rahmatullahi wa Barakatuh.
In The Name of Allah, Most Gracious, Most Merciful.
All Praise and Thanks are due to Allah, and peace and blessings be upon His Messenger.
In response to this question, the European Council for Fatwa and Research (ECFR) issued the following Fatwa:
Apart from the reason for saving it, Zakah should be paid on it if the money saved for marriage reaches the minimum (85 grams of gold) and remains in your possession for one full Islamic calendar year unless you have begun the marriage procedures and require this money.
Allah Almighty knows best.