(...)"I was hoping you could help me out with wedding kimonos, please? I keep researching and I can't figure out how many kimonos does a bride wear from the engagement to the end of her wedding day. Some say two, others say three. X. X
Also, someone told me that the bride usually wears a flower with a personal meaning in her hair, is that correct?? If they have some common flowers, do you know which are, please?? And which accessories do they use?"(...)
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Hi, Danye-Angel. Your doubts are understandable. Wedding kimono are variate and full of details, so this is a complex theme. I'll do my best to help clear it up a bit!^^
Regarding the engagement, there is no specific kimono related to a woman being fiancée. She would keep wearing her usual kimono, including long-sleeved furisode, until she got married.
For the wedding ceremony, the first thing to consider is that, like in western-style weddings, the bride and groom can go for a very traditional style, or choose a more modern one. Let's start from the most traditional Japanese-style women's wedding garment still in use today: shiromuku.
~ ~ ~ Shiromuku: Pure White
The shiromuku (translated pure white) wedding ensemble has been worn by brides in shinto wedding ceremonies since the Muromachi period (1336~1573). All the garments and accesories are white, and usually feature auspicious motifs like cranes, pine and bamboo, tortoises... - all also in white. This color is a symbol of a bride's willingness to be "painted" with her new family's standarts and ways.
The full shiromuku ensemble includes white undergarments, a furisode with trailing hem called kakeshita (or shiro-kakeshita, "shiro" meaning white), white obi (usually a super-gorgeous maru obi, or less expensive, yet also highly formal fukuro obi), white obi-age and obijime, and a heavily-decorated, embroidered over-kimono worn loose over all, named uchikake (or shiro-uchikake). The bride also wears tabi socks and zori sandals, and, as main accesories, a sensu folding fan, a small kaiken* knife, and a brocade purse called hakoseko.
*This comes from samurai women, who used to get a kaiken on their wedding day, and always kept it on their obi, for self-defense. I think the kaiken nowadays is fake, though, just for tradition.
In this detail, the rich white-on-white motifs of shiromuku are visible. Please notice the hakoseko tucked in the bride's eri (collar) and the kaiken inside a fabric tied with silk cord, tucked in her obi. Cut from an original photo from Studio Aqua.
...About the hair. Traditional brides wear a wig styled in Edo period shimada style, adorned with kanzashi (not the silk ones maiko wear, though... see their style below). Then they cover it with either a special hat called tsunokakushi, or, while outdoors, a hood that works similarly to a western's bride veil, named wataboshi.
A traditional bride wearing the tsunokakushi hat over shimada wig. The kanzashi (and in this case, the tiny detail of red inside the front hat bow) are the only colored details. Photo from Takehiro Misawa Photograph Office.
The full shiromuku look is both gorgeous and delicate. The uchikake is lined and padded so it trails beautifully, but because of that it's also quite heavy! This photo shows a bride dressed in this super-traditional shinto wedding style, with shiromuku and wataboshi, from Juin Perle. You can see the sensu in her hand, and the silk danglings that decorate the kaiken tucked in her obi.
Even with shiromuku meaning "pure white", it's very common to also see it featuring hints of red in some details. Since red is a classic auspicious, feminine-related and neutral (yes, neutral!) color in kimono culture, its presence there is still in very traditional style, just like all-white shiromuku.
Traditional brides wearing shiromuku with hints of red. It's specially common to see this color peeking from white as in here, inside the wataboshi, and in the garment's lining. Photos from Hayato Blog (left) Takehiro Misawa Photograph Office (rigth).
~ ~ ~ The Gorgeous Iro-Uchikake
Starting from the Edo period (1603-1868), a new wedding garment came for brides from wealthy and noble families. After the wedding ceremony, for the reception, they would change their all-white shiro-uchikake for another uchikake outer-garment, called iro-uchikake (iro meaning "color").
Iro-uchikake features the same auspicious kind of pattern and rich brocade we see on shiro-uchikake, only this time very colorful. Red is the most traditional base color for this kind of wedding kimono, but other tones like gold and pink are also common. Slightly more modern designs feature all kinds of color, preferably deep, rich tones like deep purple or green, and even turquoise.
A super-traditional red iro-uchikake with auspicious motifs, and another a bit more modern, deep purple and pink with sakura (cherry blossoms) as main pattern theme. Notice the kanzashi, also less traditional in the purple uchikake photo. Both from K-Bridal.
~ ~ ~ The Elegant Hikifurisode
Apart from shiromuku and uchikake, another classic kind of bridal kimono is the hikifurisode - "trailing furisode", also called hanayome furisode ("bride furisode") or kakeshita (just like in shiro-kakeshita, only without the "shiro" for "white"). Hikifurisode is typically an o-furisode* with a small trail, worn without a fold at hip-height - different from standart furisode, which, like most female kimono, is folded so the hem will go almost up to the ankles.
*All furisode have long sleeves, but they can be divided in ko-furisode (usually only worn with hakama, for graduation ensembles. The sleeves are 75-87cm long), chu-furisode (standart type, with sleeves of 91-106cm), or o-furisode (the more formal, with sleeves of 114-125cm).
Standart o-furisode (left) and bridal hikifurisode (right). Notice the absence of the fold at the waist/hip line on the bridal garment, as well as the padded trail and bridal accessories (sensu, kaiken and hakoseko). Pretty sakura-themed furisode from K-Bridal, and elegant hikifurisode from Ogiya Wedding Salon.
Hikifurisode started to be worn as bridal garment by samurai women in the late Edo era, and is popular today as a lighter (and probably less expensive) alternative to shiromuku/uchikake. More traditional brides may use it as a third change of clothes during their wedding day celebrations, after shiromuku (for the ceremony) and uchikake (for the reception).
~ ~ ~ Modern Twists!
Finally, after knowing all the traditional garments, it's time to see more contemporary-born variations of bridal kimono! There are "modern twist" versions of all of them, and even new shapes altogether. The possibilities are almost endless, so I'll just brush over a few styles!
Today bridal kimono can range from super-traditional black hikifurisode with classic motifs and tsunokakushi (from Juin Perle) to crazy leopard-print butterflies and foofy ruffles uchikake (from Scena D'Uno) - and every style in between! ;)
About the hairstyle... Both traditional bridal headwear tsunokakushi and wataboshi used to symbolize a bride's obedience to her husband (specially the tsunokakushi, which was worn to hide the brides "horns of jealousy"). So, maybe for this, many japanese brides today choose not to wear them, and go with just the shimada wig, or a more modern hairstyle instead.
This is probably where enter the flowers you mentioned - it's indeed quite common to see modern japanese brides wear their hair up on a formal bun, adorned with flower kanzashi, or even natural flowers. The styles go from soft and discrete to wild, giant bouquets, so I think it's all up to each lady's taste on her special day!
Examples of modern bridal hairstyles paired with shiromuku and uchikake.The first on the left is based on traditional nihongami (japanese hairstyles), but has the boldest flower arrange! The other two show clear western influence, in a variety of color schemes. They all look so pretty! Left photo from Statice Dress, right from Mimatsuya. Sorry, couldn't find the source for the middle one!
Some brides go for a classic shiromuku with new hints of color - specially pink - or made of other fabrics instead of/ mixed with silk. Organza and other light, see-trough fabrics are also very popular, with both all-white ensembles and colorful uchikake.
A white-and-pink modern "shiromuku"...
Lovely translucent iro-uchikake in pastel tones...
Pink and white floral iro-uchikake. From Bienveil.
These designs from Scena D'Uno mix shiromuku with western-like veils... 
A Yumi Katsura bridal design. Super long-trail deep blue hikifurisode with peonies and golden motifs. The layered-like hem and eri (collar) are a reference to the multi-layered kimono of old times, and the bride's hair is styled in traditional japanese way. The modern, intricate and delicate kanzashi is simply amazing!
A super-long trailing reinvented shiromuku, with traditional japanese tsunokakushi,
modern hairstyle and western-classic lace! By Yumi Katsura.
...Can you tell I'm a fan of Yumi Katsura? Notice the round bouquet - japanese-style bouquets are often ball-shaped, tied in colorful cords and hanging like a flowery purse. This one is midway to a western-style, though...
A more classical japanese-style bouquet. So cute!
And this mixes the traditional "shiromuku + red" and japanese ball bouquet style with modern elements - and fruit! - for a chic, trendy look. The bridal kimono possibilities are endless!
...So, this is the basics about ladies' wedding kimono! I hope this (not so small) article helped you a bit, Danye-Angel! Thank you for your question, it was a lovely subject to research - so many pretty kimono photos! Any other doubts about wafuku, don't hesitate to ask! ^^