The flowers are very large, 2.5 to 3 inches in size with a 'foxglove' appearance. they are very beautiful.
If you want very mellow tea with a hint fo native sweetness, gather the blossoms as they are 3/4 open or within one day of opening. THe color is richest then. If you prefer your tea with a hint of bitter (some people do) then gather the older flowers which are just starting to brown at the tips. Fresh flowers yield a light violet tea. Dried flowers a light amber tea.
This year I am making a paulownia flower cordial by steeping five dozen flowers in boiling water (3 liters), granulated sugar (2KG), 100 gram of citric acid and 8 zested, sliced lemons. Let the whole thing set covered for 48 hours, then filter and freeze in pint bottles. Later dilute with soda water to taste. Delicious - similar to elder flower cordial, but a rosy pink instead of yellow.