Tambasasayama City: A seasonal feature of summer: The lotus flowers in the southern moat of Sasayama Castle ruins have begun to bloom

The southern moat of the ruins of Sasayama Castle in Tanba Sasayama City is completely covered with lotus flowers.

This lotus is an endemic variety called "Sasayamajobasu," and has few petals and large flowers.

The lotus flowers disappeared once around 2005, but after many efforts such as eradicating invasive species and reintroducing lotus flowers, they bloomed for the first time in about 15 years in 2019. They are expected to reach their peak between late July and mid-August. Please come and see the revived lotus flowers .

[City Hall website is here]

The past when lotus disappeared

Currently, the lotus flowers bloom in the southern moat of the ruins of Sasayama Castle, but they suddenly disappeared around 2005.

The cause of this decline remained a mystery for some time, but in 2013, at a "Children's Conference" where elementary school students make suggestions about city government, a sixth-grade student at Sasayama Elementary School voiced a suggestion that the lotus flowers should be brought back to life. This led the city to begin investigating the cause and working towards bringing the flowers back to life.

When they began their investigation, they found that a similar phenomenon had occurred at Saga Castle in Saga Prefecture, where they had found a case in which lotus flowers had recovered after the eradication of the invasive red-eared slider turtle.

They assumed that red-eared sliders were the cause and began efforts to revive the lotus plants.

Efforts to revive lotus

In 2014, in an effort to revive the lotus flowers, the extermination of red-eared sliders began, and the following year, the city, citizens, businesses, and Kobe University came together to form the Sasayama Agricultural Capital Invasive Species Control Council, and began full-scale extermination efforts.

We mainly used nets containing bait to set up bait traps to capture red-eared sliders.

In addition, we held a dredging event in collaboration with local residents. We drained the water from the moat and caught 1,221 fish using a huge beach seine net over a five-year period from 2014. We also adjusted the water level, analyzed soil and water quality, conducted fertilizer application experiments, and transplanted lotus root seeds.

Lotus resurrected

These efforts bore fruit, and in the summer of 2019, the lotus flowers bloomed for the first time in 15 years.

This lotus revival effort, which was undertaken by the whole community, was selected for the Japan Nature Conservation Award 2021, which recognizes outstanding nature conservation and biodiversity preservation activities.

Currently, the lotus flowers have spread so far that they fill the entire southern moat, restoring the area to its former glory.

A summer tradition

The lotus flowers have started to bloom again this year.

The best time to see the flowers is expected to be from late July to mid-August.

Lotus flowers close their petals in the afternoon, so if you would like to see them, we recommend coming in the morning.

Sasayama Castle South Moat

Address: 15-1 Higashishinmachi, Tanba Sasayama City (South moat of Sasayama Castle ruins)