I bought my wife a bunch of flowers and then before giving them to her I realised this may be inappropriate during the three weeks.
Is this a problem or can I go ahead and give them to her?
Yes you may give them to her. The only things we abstain from regarding happiness during the three weeks are music, and purchasing something that would cause us to make shehechiyanu. The bracha of shehechiyanu is inappropriate during the three weeks, because we don’t want to say that we are happy for this “time”, as it is not a happy time.
Enjoy the flowers