Birthday
HydrangeasIn the mountain forests of Japan grows a flower that seems to turn to glass after rain: its snow-white petals become transparent, revealing their veins and raindrops, and when the sun comes out the flower turns white again. This is Diphylleia grayi, known as the "skeleton flower" or "glass flower". Here is what it looks like, why it turns transparent, where it grows wild, whether it can be grown in Ukraine and which other plants change their appearance.
What the skeleton flower looks like
Diphylleia grayi is a herbaceous perennial in the barberry family, 30–60 cm tall. The genus name means "two leaves": a flowering stem usually carries two large lobed leaves that look like open umbrellas. In May–July clusters of small white flowers 2–3 cm across appear above them, followed in late summer by dark blue berries on reddish stalks. The species is named after American botanist Asa Gray, who studied the similarities between the floras of East Asia and North America.
Why the petals turn transparent
The white colour of the petals is not a pigment but an optical effect. The petal cells are loosely packed with plenty of air between them, and light is scattered as it bounces at the boundaries between air and cells, so the petal looks white. When it rains, water fills those spaces. Water and cells have similar refractive indices, scattering almost disappears and the petal lets light through like glass. Once the petals dry, air returns and the flower turns white again. The trick can repeat many times.
Where it grows
In the wild, Diphylleia grayi grows in moist, shady mountain forests in Japan, on Honshu and Hokkaido, and on Sakhalin. It has two close relatives: umbrella leaf (Diphylleia cymosa) from the Appalachians in the USA and the Chinese Diphylleia sinensis. This split distribution is a classic example of the link between East Asian and North American floras that Asa Gray studied.
Sankayo: a flower of Japan's mountains
In Japan the plant is called sankayo, "mountain lotus leaf", after its large rounded leaves. It grows in the subalpine zone and flowers during the tsuyu rainy season in June, so photographers head to the mountains of Hokkaido and the Japanese Alps to catch the "glass" flowers after a downpour. For many visitors it is as much a seasonal symbol as cherry blossom in spring or red maples in autumn.
Can you grow it in a garden
Yes, if you recreate mountain-forest conditions. The plant is frost-hardy but dislikes heat and drought, so in Ukraine it does best in the western and northern regions.
- Position: shade or part shade, for example under trees, sheltered from midday sun.
- Soil: loose, humus-rich, slightly acidic and consistently moist but never waterlogged.
- Care: mulch with leaf mould, water in dry spells; no winter protection needed.
- Propagation: divide rhizomes in spring or sow seed, which is slow; seedlings take several years to flower.
Look for it at specialist nurseries selling rare shade plants. Good companions in a shade garden are hostas, ferns, astilbes and epimediums.
Other plants that change their look
- Confederate rose (Hibiscus mutabilis) changes flower colour from white to crimson in a day; see hibiscus legends.
- Bigleaf hydrangea turns blue on acidic soil and pink on alkaline soil.
- Victoria water lily opens white and turns pink on the second night.
- The sensitive plant folds its leaves when touched; see mimosa.
For more remarkable plants, see the largest flowers in the world and the most unusual trees.
Frequently asked questions
Why is it called the skeleton flower?
After rain its petals turn transparent, leaving only the fine veins visible.
Can I make the flower transparent at home?
Yes, by spraying it with water; it turns white again once dry.
When does Diphylleia grayi bloom?
From May to July, depending on the climate.
Is it poisonous?
Like many barberry-family plants it contains alkaloids, so do not eat the berries or roots.
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Author: Maria Svitlovir
Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.
