This Sunday night/Monday is Tu B'Shvat, which the first Mishna of Mesechta Rosh Hashona says is "Rosh Hashona of the trees". The Bnei Yisaschor writes in the name of previous tzadikim that one should daven for a beautiful esrog on Tu B'Shvat. The Ben Ish Chai composed a tefila to say on Tu Beshvat for this. You can also find tefilos for this in Likutei Tefilos. (Pages 72-73 in this PDF) It is also a day to daven for livelihood, children and other things.