This year’s cherry blossoms have already started to appear! A special cherry blossom event is being held in the interior courtyard of the Fukuoka Castle ruins from March 28 to April 8, 2012, during which time the blossoming cherry trees are illuminated for nighttime viewing. The event, put on by Fukuoka City, is open from around 5:00 p.m. every day on the dates mentioned above, and seats are available so you can sit and enjoy the trees and the starry sky above (visitors are allowed to bring in food and drinks). Other cherry trees around Maizuru Park are also illuminated during this period (a map is available here in Japanese).
Admission to the courtyard viewing area is 300 yen (the price includes a small snack), and the illuminated trees in other parts of Maizuru Park can be seen for free. Last admission to the courtyard is at 9:45 p.m. The location of the castle ruins can be seen here–the castle ruins Maizuru Park can be reached in 10-15 min. on foot from Ohorikoen Station (Kuko Subway Line) or Ropponmatsu Station (Nanakuma Subway Line), and also by bus.
The best time to see the blossoms will be in early April, although it may be less crowded if you go before then. More information on cherry blossom spots and the best times for viewing the flowers can be found here.