Even though March is a great time to visit Mito because of the plum festival, there is much more to see that makes this small Ibaraki Prefecture city a great place to visit.
You do not want to miss Kairakuen Garden and the 3000 beautiful plum trees. While you're here, learn about how this garden began. Nariaki Tokugawa was a feudal lord who loved the plum trees not only for their beauty, but also as a source of food for his warriors. Make sure to climb the hill and enter Kobuntei, a three-story historic wooden building that also provides spectacular views overlooking the garden. Kairakuen is great all seasons with blossoming plum trees, cherry trees, wisteria, azaleas, and a bamboo forest.
If you're fortunate enough to be there during the three day Umeshu Festa, enjoy the plum wine -asting tent with 166 wines and sake from all regions of Japan. For 800 yen (around $7) you receive a cup and have one half hour to taste as many of the wines and sake as you want. I will warn you that after about 60 they all start tasting the same, but it will sure provide a small buzz. While walking around the garden keep your eyes out for the beautiful Daurian Redstart bird that travels all the way from Tibet and Northern China to sit out the winter.
Another great area of Mito is the Kodokan, which became an Educational Heritage site. Tokugawa built a clan school system that was envied throughout Japan. It provided classroom training, along with a martial arts area, a riding ground, Kashima shrine, and a Confucius shrine. From Kodokan, directly across the highway bridge, are the Mito Castle ruins with the main gate currently under restoration. Walk down the steps where there are many historical markers and gates with explanations in English.
There are plenty of museums throughout the area along with the Mita Art Tower complex with a concert hall, a theater, and a contemporary art gallery. You can find all types of festivals year round. While strolling the streets you may run into Mito Komon and his helpers as they provide a walking drama about Mitsukuni Tokugawa, a former vice-shogun. He will invite you to have your picture taken with him.
As you can see Mito is much more than just plums, and it is only two hours by train from Tokyo. Plan on a full day to tour this very nice city. Every place you visit provides English brochures.