Sukkos ayin ches, 2017

1. It's common knowledge that you can only use those lulav holders made out of palm leaves to hold the lulav. This almost universally acknowledged fact is false. You can use rubber bands if you like.
See MB 651 SK 9 and 10, and Aruch Hashulchan there sk 5. You really don't need the poskim to hold your hand, ,because it's practically mefurash in the Gemara there after the mishna on 36b about Reb Yehuda and the Rabannan about iggud. Once you know that although binding the three minim is not necessary, but is viewed in halacha as an enhancement of the beauty of the lulav or the kiyum hamitzva, and once you know that whatever is used for noi is not chotzeitz, there's nothing to talk about.
The reason this mistake is so popular is because when it comes to some other interposition between the hand and the lulav, perhaps even a ring on your finger, the issue of chatzitza and the din of min b'mino do become relevant. That is not the case where the other material is serving the mitzva by enhancing the kiyum or the appearance.
The Kappos Temarim there does say that chasidim and anshei maaseh use palm holders, like we do; but if you'll look at the KT inside, you will quickly realize that his first teretz is a reeeeal stretch - a concept completely unheard of l'halacha -  and that his second teretz is most logical. True, he does say that chasidim and anshei maaseh use the palm leaf holders, but I'm neither, and you probably aren't, either. If it's easier, or nicer, to use Raffit (really great stuff!! Check out their entire line!!) or ribbons or leather or Livestrong rubber wrist bands, it's 100% fine.
This is especially useful towards the end of the yomtov, when things are starting to fall apart. Just toss the humdrum holder and use something beautiful.

2. Black leaves on aravos are fine. The din of shinui mareh being considered serious enough to passel is only applied to Esrogim.

Allow me to qualify "fine." It's not beautiful, and if you have the option of using new green ones, you certainly should.

I verified the black leave answer with my father in law who said that as long as they're not dry they're kosher.


In a stunning coincidence, this morning, Hoshanna Rabba, I was davening in the Yeshiva of Staten Island in front of an old friend. He is an adam chashuv by any standard: a baal mussar, an life-long expert marbitz Torah - eight grade rebbi for forty years, now a tenth grade rebbi in one of the most intense yeshivos in the US, and so forth. His wife asked me not to mention him by name, because he should have gotten over his annoyance with greedy aravah sellers and gotten fresh aravos, and le'mayseh rubber bands are not exactly shpitz hiddur, but he lives on Pleasant Plains Avenue in Staten Island.
Here is a picture of his lulav.

Blackened Aravos and Rubber Bands! How nice of him to provide an illustration for this post!

UPDATE

Reb Avrohom Wagner said a he'ara on my first point. He notes that the Mishna Berurua in 651:8 brings from the Tshuvos Agura B'ohelecha that he's "metzadeid" to allow those lulav holders even though the lashon of the poskim is that they should be "kashur," which might imply knots. Reb Avrohom says that the MB's is not comfortable with the Mishna Berura's reliance on the Agura B'ohelehca. 

Here are the words of the Mishna Berura:

ח בקשר גמור - ולא בעניבה דאין זה קשר הנאסר בשבת ויו"ט ולא מקרי אגד ועיין בתשובת אגורה באהלך שמצדד דמה שנוהגין העולם שלא לעשות קשר אלא עושין מן עלי לולב כמין בית יד ותוחבין הלולב בו ג"ז בכלל קשר ע"ש

This is how I responded in the comments.

I don't understand what you mean. Bishlema if egged is a din deoraysa for the tzura of the mitzva, you can be mechaleik between kesharim. But if it's meshum noi, what possible logic is there to say there's more noi if it's a kesher shel kayomo? Anything that firmly holds them together is noi, whether the concept is based on appearance of hiddur in the kiyum of the mitzvah. This is, indeed, what the Agura Bohalecha says in response to machmirim - 

ואנוכי הדיוט לא ראיתי טענה מספקת דהא לדידן דלא צריך אגד אלא לנוי וכי גזירה היא ב׳ קשרי' ודאי דהיינו טעמא דבב׳ קשרים איכא נוי ומהדק יפה ולא משלפי לכאן ולכאן משאיב בעניבה

I admit, though, that the Mishna Berura seems to hold that you do need a double knot mamesh, and he only mentions the Agura B'O in a lukewarm way - עיין בתשובת אגורה באהלך שמצדד - like a bedieved. I am confident that in the case of a firm binding, unlike a mere bow, it's hard to believe there's anything to worry about. But I was wrong about the Kugel, and maybe I'm wrong now, too. Decide on your own.