Why does it say "Serufah" (feminine)?
Radak #1: "Ben" is feminine, like "Ben Pores Yosef" (Bereishis 49:22).
Radak #2: "Serufah" refers to Chanah (refer to 80:16:1:2-5), or to Gefen. Malbim - the building (Beis ha'Mikdash) was burned, and Chanah was cut.
What is "Kesuchah"?
Rashi: The Targum of "Lo Sizmor" (Vayikra 25:4; do not cut the branches) is Lo Sichsach. Radak citing Shocher Tov - it does not say uprooted, rather, cut - everything cut grows back.
What is "mi'Ga'aras Panecha"?
Radak: Your rebuke was to hide Your face from Yisrael.
Why does it say "Yovedu"?
Rashi: They always dwindle and perish due to Your rebuke and anger.
Malbim: It is proper that the Chazir and Ziz Sadai perish amidst Your rebuke, for they ruin the vine!