Roses or her favorite flower are always nice, even for anniversaries. If you can find a place still selling potted plants, you could even get her something to plant in the spring, so it won’t be a present that will just wilt and die and be thrown away. My dad does that every so often for my mom, and she always enjoys getting to plant them in the spring (their anniversary’s in September, along with their birthdays).
Finding something little and cute - like a little figurine of some sort you might see in a Hallmark store - that she can put on her desk and look at now and again to think about you is another idea, or something to add on to the flowers. Sometimes it can depend on the woman and what sorts of things she likes.
