Question: Why are people discouraged from sending flowers to Jewish funerals?
Answer: Jewish law demands immediate burial. At the most, Jews should be buried within three days of their death. Non-Jews tend to keep their dead for longer periods before burial.
Historically, to offset odor from the decaying body, non-Jews often used flowers and spices. Due to the immediacy of burial in Jewish practice, flowers and spices were not needed at Jewish funerals. Furthermore, the absence of flowers at Jewish funerals became a way to distinguish between Jewish practice and non-Jewish practice. Thus, it became customary to discourage flowers at Jewish funerals.
Despite the custom of flowerless funerals, Jewish Law in no way forbids flowers at funerals. So today there are Jews who do welcome flowers at funerals. And in Israel today, many people place flowers on graves, particularly in military cemeteries.