WASHINGTON (AP) — Stepping gingerly over the lawn in their spiky heels, first lady Jill Biden and Yuko Kishida, the wife of Japan's prime minister, planted a cherry tree at the White House on Monday to honor decades of friendship between their countries.

"This is how you always plant a tree," Biden said, laughing about their shoes as she and Kishida used gold-toned shovels to scoop soil and toss it into a hole and around the base of a sapling Yoshino cherry tree on the south grounds.

Kishida is on a rare solo visit to the United States. It's the first time the spouse of the prime minister has traveled alone to the United States, and Kishida visited at Biden's invitation, according to the Japanese embassy in Washington.

She is spending part of the week in Washington to promote friendship between the U.S. and Japan, as well as cultural exchanges, the Japanese government said.

Biden took Kishida to the Oval Office to see President Joe Biden, the White House said, and hosted her for lunch. Among those invited to the women-only meal were Rep. Doris Matsui, D-Calif.; Maki Onuki, principal dancer at the Washington Ballet; and Akiko Iwasaki, immunology professor at Yale University School of Medicine, according to the first lady's office.

The new sapling is a Yoshino cherry tree that was propagated from a cutting from a cherry tree that was planted on the south grounds in July 2017, the White House said. It was planted near the East Wing. The White House has 23 other cherry trees across the 18 acres.

The meeting between Biden and Kishida was rescheduled from January when Prime Minister Fumio Kishida and President Biden met in the Oval Office. Kishida's wife accompanied him on the trip. But Jill Biden was unable to host Yuko Kishida at the time because the first lady was recovering from a surgical procedure performed two days earlier to remove several cancerous lesions from her skin.

It also comes before next week's state visit by South Korean President Yoon Suk Yeol and first lady, Kim Keon Hee.

President Biden has looked to build closer security cooperation with Japan and South Korea at a time of shared concerns about a restive North Korea and a more powerful China. He has sought opportunities to help the historic rivals improve their long, fraught relationship as the Indo-Pacific region becomes increasingly complicated.

In March, South Korea announced a plan to compensate Koreans who performed forced labor during Tokyo's colonial rule that doesn't require Japanese companies to contribute to the reparations.

Biden hailed the step as a "groundbreaking new chapter" in cooperation between the countries. Yoon followed up by visiting Tokyo later in March for talks with Kishida. It was the first summit between the two nations' leaders since 2011.

The U.S. and Japanese spouses also were meeting several weeks before Kishida hosts the annual Group of Seven summit of leading industrialized nations, including the U.S., in mid-May in Hiroshima, Japan.

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Associated Press writers Aamer Madhani in Washington and Mari Yamaguchi in Tokyo contributed to this report.