In the Kyushu region, tea is including as a part of a traditional wedding gift set.
Tea as an engagement gift is called yuinōcha (結納茶), and as part of the wedding gift set in Kyushu it is specifically written as (御知家, ocha) and it literally means a wise family.
The tea plant is difficult to transplant once it is mature.
So the idea is that the new couple will start a family and it will take firm roots.
There are various explanations about why tea is used as an engagment gift in Kyushu.
For example, another one is that tea leaves never change color or wither throughout the year, so they are a symbol of perseverance for the wedding couple.
The tea used is bancha, which is a low grade tea.
This happens because a high quality tea is said to steep well: yoku deru. But deru also means to leave, so it is an undesirable word at a Japanese wedding.
However, outside of Kyushu, tea isn’t normally used as a wedding gift.
The reason is the types of expressions that can be spelled with the symbol for tea: 茶 (cha), such as chakasu (to make fun of), and chacha wo ireru (to interrupt a conversation).