Seed collecting in Japan by Timothy Walker

Seed collecting in Japan by Timothy Walker

Seed collecting in Japan by Timothy Walker

Japan is fascinating country botanically with 1 in 3 of the 4,500 species growing only in Japan.  Much of the land is mountainous and thus it is a rich source of alpine species.

Timothy is the former Director of the University of Oxford Botanic Garden and Arboretum. He joined an expedition arranged jointly by RBG Kew and the Alpine Garden Society to collect seeds in Japan in the late 1980s. In our January 2022 talk Timothy shared with us this fascinating trip, introducing us to some of the plants the team discovered and some of the unique aspects of Japanese life.

Japan comprises over 1000 islands, four of which are the largest including Hokkaido where the trip focussed its collecting. Due to strict conservation laws, 85% of the land remains wooded, mainly with Crytomeria and Abies. Japan has a rich flora, 30% is endemic.

Timothy gave us a visual and information feast about some of the areas the trip explored and notable plants encountered.

Konsei pass. Oplopanax horridus, a woodlander to 4 foot high, red berries and spiny all over. Cornus kousa, a well known plant in cultivation. Pollen is fired out of the anthers at a velocity 9000 times the speed of gravity! Lilium tigridum and L. auratum grows on roadside verges, the former widespread and the latter locally restricted.

Mount Hayachine. The serpentine rock is rich in Magnesium, with rare plants adapted to tolerate this, but also widespread is Acer palmatum. Sanguisorba obtusa only grows on this mountain. Leontopodium hyachinese grows at the peak.

Rebun. This island is an ancient volcano, gradually eroding away. @salpine’ plants grow here at sea level such as Mertensia asiatica, very compact Artemisia sericea, Sedum erubescens and Hytolephium cauticlum growing in rock fissures. The large rocks and scree provided inspiration to Timothy when rebuilding the rock garden at Oxford Botanic Garden.

Rishiri. This is a young volcanic island, where familiar Skimmia japonica and Actinidia kolomicta grow. On the coast is Lycopodium anonitum, a diminutive plant whose ancestors were trees that became coal. At the mountain Hypericum kamtschaticum and Salix reinii shelter in rock fissures.

Tomakomai Forest Station. Dominated by birch, other plants here include fern Japonobotrichum vulgare and climbing Shinsandra chinensis, with red fruits in autumn and mature stems that are aromatic when burnt. Primula japonica clother the sides of streams

Mount Apoi. Chrysanthemum yezoense is named after Yezo, the former name for Hokkaido. It grows happily as a rock garden plant in the UK. In September the plants, growing up to 3ft round, become smothered in large pure white daisies that age to pink. It’s now on our wish list!

Jackie Hunt, Gardener, Turn End