The Gemara in the sixth chapter of Masechet Berachot teaches that a person who is ignorant of the Halachot of Berachot must fix his situation to avoid transgression by going to a Talmid Hacham "Me’ikara"-from the outset-before he makes a mistake and violates the Halacha. Rabbi Yonatan Eibshitz (1690-1764) derived from the word "Me’ikara"-literally meaning from the beginning- that the first subject of Halacha that should be learnt is Berachot. That is why Masechet Berachot is the first tractate in the Talmud.
Learning the Halachot of Berachot does not merely mean knowing what Beracha to make on different foods. Knowing that the Beracha on an Avocado is Ha’etz and a banana is Ha’adama is learnt by understanding nature. Even if one knows the correct Beracha for each food, the Halachot of Berachot teach, for example, the proper order to recite the Berachot.
For example, one simple case, which many people are not aware of, is when a person plans to eat peanut and grapes. The Beracha on peanuts is Ha’adama, whereas the Beracha on the grapes is Ha’etz. Most people would assume that one should recite the Beracha on the grapes before the peanuts, since generally Ha’etz comes before Ha’adama, and grapes are one of the "Shiva Minim"-the seven special species of the land of Israel and because he may prefer the grapes to the peanuts.
Nevertheless, the Shulhan Aruch in 211:1 rules that if one is going to eat a radish and an olive, he may recite the first Beracha on either one he wishes. Even though the olive is one of the Sheva Minim and its Beracha is Ha’etz and he prefers it. Maran repeats the same principle in 211:3, as well.
One must know this rule: When it comes to two foods of Ha’adama and Ha'etz, there is no special preference for the order of reciting Berachot.
SUMMARY
When it comes to two foods of Ha’adama and Ha’etz, there is no special preference for the order of reciting Berachot.
