The Order of Prayer on Hoshana Rabbah, 11 Seifim: 1. On the seventh day, Hoshana Rabbah, it is customary to sing lots of psalms, like on Yom Tov. Rem"a: We do not say "Nishmat, " we do say "Mizmor l'Todah," we say "Ein Kamocha" and "Shma Yisrael" [in the Torah service] like on Yom Tov. We sing the kaddish after Mussaf in the Yom Tov tune. One normally does not do weekday labor until after leaving the synagogue. We say the song "Zchor Brit" when there is a circumcision on Hoshana Rabba, and we say it before "Ana hazon hin...." The early rabbis z"l wrote that the shadow of the moon on Hoshana Rabba evening holds a sign for what will happen to a person and their family in that year. There is one who writes not to be concerned with this so as not to upset one's fortune and also because many do not understand this matter fully. It is better to be pious and not to investigate the future. This is how it seems to me. We have lots of candles, similar to Yom Kippur. Those who are careful have the practice of immersing themselves before dawn, just like on the day before Yom Kippur (Minhagim). There are some who wear a kittel like on Yom Kippur. This is because on the holiday [of Sukkot], the matter of water is decided. It is customary to unbind the lulav. We circle seven times and say many prayers about water.
2. We take a willow branch on this day, besides the willow in the lulav, and we do not bless on it. Rem"a: Some have the custom wherein the shamash of the synagogue brings willow to sell just like the custom in the Temple when it existed (Ra"n ch. "Lulav v'Arava").
3. There is one who says that even on this day, we circle with the lulav and not the willow. This is not our practice. Rather, we circle also with the willow.
4. The minimum quantity for this willow is even one leaf on one branch. Rem"a: However, it is unseemly to have one leaf on one branch (Tur in the name of Rav Hai) and the custom is, therefore, to make the hoshanot pretty in the name of "This is my God and I will make Him beautiful." The minimum length is the same as for the willow in the lulav. Rem"a: Everything that invalidates the willow in the lulav invalidates this willow (from Ra"n ch. "Lulav v'Arava"). We beat it on the ground or on a vessel twice or thrice. Rem"a: There are those who say that it must be shaken (Tur quoting Rash"i). It is customary to do both; we shake it and then beat it.
5. It should be taken alone. Nothing else should be bound with it. However, if there is something else in one's hand, it is not a problem.
6. One cannot fulfill the obligation with the willow from the lulav, even if it is lifted twice, once as a lulav and once as a willow. There are those who say that the obligation is fulfilled this way.
7. There is one who says that one cannot take [the willow] with the lulav when fulfilling the obligation [of lulav] until after making the blessing and shaking it at the beginning, and if [the willow] is taken, the sin of adding things is committed. After the first shake, it can be taken with the lulav, and obviously during the circles. Even though when he wrote that taking it is the sin of adding things, that was a mistake, in my opinion, in any event, there is no loss in heeding his words. He further wrote that after the taking and shaking, the willow alone should be held to show that it is obligatory, and when beating it, it alone should be held, and one thereby fulfills their obligation. Rem"a: The widespread practice is to take the willow with the lulav at Shacharit when shaking and circling until the beating, at which point the willow alone is held. It is better to not hold it together with the lulav at all. It seems to me that even one who holds it with the lulav should put the lulav down after the circles and hold the willow alone, otherwise known as the hoshanot, during all of the supplications about water. We shake the hoshanot when we say hoshanot and afterward beat them.
8. There is one who says that even when the willow from the lulav is discarded, it should not be stepped on (and see 21 regarding tzitzit).
9. There is one who says that it is forbidden to benefit from the willow after it is taken unless it was stipulated from the beginning because each day it is dedicated to the function of its mitzvah. Rem"a: It is customary to store the hoshanot for the baking of matzos so as to do a mitzvah with them (Mahari"v and Mahari"l).
10. There is one who says that a Jew should be careful not to cut the mitzvah willows from a non-Jew's field, even with the non-Jew's permission.
11. If Hoshanah Rabbah falls on Sunday and a non-Jew cut the willow on Shabbat and brought them, they are valid. Rem"a: That said, if a Jew ordered him to cut them and this is publicly known, one should be stringent if there is another willow (Beit Yosef quoting the Rashb"a's responsa).