He read: "Roses are red, violets are blue. I think today is a good day to tell you that I love you."
Earlier in the trial, Pistorius - who claims to have shot the model in the mistaken belief she was an intruder - had admitted he could not face opening the card or Reeva's gift of a framed selection of pictures, for many months after she died, but finally did so on her birthday last August.
Given another chance to address Judge Thokozile Masipa today, Pistorius said he was "terrified," "scared" and fearful for his life in the incident, thinking there were intruders in his home, adding he fired off his gun "before [he] could think".
He added: "I was thinking about what could happen to me, to Reeva. I was just extremely fearful."
Legal teams on both side how now asked for a two-week adjournment to the case, beginning on Friday (18.04.14), and the judge has promised to consider the request and make a ruling tomorrow (16.04.14).
The defence is then expected to conclude its case by mid-May, but another postponement is likely before concluding arguments.