Answer :
If im correct I will have to say the last one Roses and hydrangeas which require more rain fall--do well I east Texas
Answer:
Roses and hydrangeas-which require more rainfall- do well in East Texas.
Explanation:
Dashes are used with wide different purposes, in the case we are answering about they are used as a replacement of the parentheses. For this case it is commonly used the dash known as em dash, this one is a bit longer than the en dash.
I hope this answer and its brief explanation helps you.