The etiquette has precise rules also comply with regard to dress the groom’s mother should wear during the wedding. If you obey the rules of the classic etiquette, it is the mother of the bride buys her dress first, then does know the details of the same to the groom’s mother so that it can purchase a dress that matches with the bride’s mother, without to be identical. If the wedding is very formal, groom’s mother should wear a long dress or a tea dress.
Mother and mother-in-law in white: there must have been some miscommunication.
However, the modern etiquette was a bit softened. It would be nice that mother-in-laws were discussing their respective outfits in order to avoid the same color or prevent a have a formal and the other too casual clothes. Groom and bride in this case may act as intermediaries, indeed, could be the bride to want to choose the color according to the theme of the wedding and bridesmaids dresses.
In the event that the bride would leave full freedom of action, the groom’s mother would do well to follow some rules:
1) the dress should reflect the age : not good to see a mother-in-law at the wedding dressed like a teenager
2) the dress must enhance it : should be accompanied by sincere friend to the dress enhances the best features and does not show what is hidden
3) long dress or not? Yes, if the wedding is in the evening, not if it is by day, better the short dress. You may not see in general invited you to 12 go around with long dresses worthy of an official evening with Queen Elizabeth
4) color : the mother-in-law (and invited in general) should never be rival to the bride, then banned the white, ivory and champagne. Prohibited even the blacks clothes, as well as, given the age, it would be better to avoid the red or overly bright colors. Better opt for pastel shades or beige, blue, light green, light pink or even silver.
5) do not overdo it : do not overdo it with whimsical fashion apparel, with colors too particular, too many extras, with makeup, with necklines, no need ever to compete in overcoming the bride or mother of the bride
6) yes or no caps? It depends on the wedding dress code. Contact the bride to see if appreciates them. Then ask the mother of the bride and the other invited if you wear them if you are the only ones who want to wear a hat, then avoid it.