The cherry trees in this park need work to stay. Saitama prefecture's own page explains why: Somei-yoshino is propagated by grafting, so every tree is a clone of every other. They open on the same day. They also age at the same rate, and the prefecture puts that span at sixty years, or eighty, depending on who you ask.

Decline in cherry trees is a national problem, the same page says, and this park has about a thousand of them. A thousand trees of one age is a thousand trees that will need attention at the same time.

Omiya Park opened in 1885 as Hikawa Park, beside the shrine of the same name, which makes it the oldest prefectural park in Saitama. There is a stand of red pine as well as the cherries.

Since 2005 a group of volunteers called sakuramori, cherry keepers, has worked with the prefecture on the trees: thinning where they have grown too close together, replacing the soil around the old ones. It is maintenance by subtraction rather than planting, which is the opposite of what most people picture. All of it happens under the same branches that people sit beneath in April. The timing given on this page is not the prefecture's; it comes from the weather record for Kumagaya.