Torah Temimah citing Nidah 19b: It says here "Shelachayich Pardes Rimonim," and it says "v'Shole'ach Mayim Al Pnei Chutzos." A Gezeirah Shavah teaches that the same blood that sends women from their husbands is equated to water (It is Machshir. Tosfos ha'Rosh - since another source teaches that Dam Nidah is Machshir, the Gezeirah Shavah teaches that yellow blood is Machshir.)

Rashi: A dry land is called Beis ha'Shelachin. One must irrigate it constantly. Sadeh Beis ha'Ba'al is better (rain suffices for it). Here he praises - your dry Shelachayich (Beis ha'Shelachin) is full of all good, like a pomegranate orchard. This hints to the small of Yisrael. They are moist with good deeds like a pomegranate orchard.

Rashi ¹ (Nidah 19b): Shelachayich (Dam Nidah, which is sent from a woman) is like a pomegranate orchard, which is locked to guard it. So Bnos Yisrael lock their genital openings while they are Nidah, to avoid intimacy with their husbands.

Seforno: Lands not good for Peros were like a pomegranate orchard. Even though [David] had times of affliction - war with Amon and Mo'av, all his days ² were wealth and honor.

Malbim (Melitzah): Now He comes close to the locked garden, and praises everything in it. It has fruits good to eat - "Pardes Rimonim." It has nice fragrances - "Kefarim Im Neradim." Just like Korbanos, which were to cause the Shechinah to constantly be amidst His nation, their relation to Shechinah ha'Kodesh was like food and fragrance to the Shechinah of the Nefesh in the body, like the Kuzari writes. Korbanos are depicted as food - "Korbani Lachmi l'Ishai" (Bamidbar 28:2). Via Korbanos, the spiritual separated from Nefesh ha'Chai and ha'Tzome'ach, when thought and Kadosh intent join with them, they are prepared for Shechinah of Elokus. Food depicts physical Avodah. Pomegranates hint to the 613 Mitzvos, like the number of its seeds. They are the food of the Kadosh King. Also refer to 4:13:3:3.

Seforno: This is to understand and give rulings - had David not engaged in Torah, Yo'av would not have [succeeded] in war (Sanhedrin 49a).

Malbim (Melitzah): This includes additional warnings and fences [above the 613 Mitzvos].

Rashi: They are kinds of fragrances.

Seforno: This refers to [good] Midos - "Lo Yeshev b'Kerev Beisi Ose Remiyah