Melissa's Travel Adventures

Ajisai / Hydrangea (native)

Hydrangeas bloom everywhere in Japan at the beginning of summer, around June. Japan is quite famous for them in summer. These huge, gorgeous flowers can be white, pink, purple, or blue. Fun fact: hydrangeas that are not white will produce flowers of different colors depending on the pH of the soil. More acidic soil will produce flowers that are more blue, and more alkaline soil will produce flowers that are more pink.

I was very excited to see these flowers because I saw them so much when I worked for Divine Floral. I had no idea that hydrangeas could come in such intense colors or variable shapes.

Shimotsuke / Japanese spiraea (native)

It is naturalized in the east and central United States. In some areas of Japan, the population is decreasing due to damage by deer. It is only used as an ornamental plant by humans.

Kohirugao / Japanese bindweed (native)

Another name for this species is Japanese false bindweed. Though, it’s possible that the Japanese bindweed and Japanese false bindweed may be different species, because the Internet hasn’t been clear about scientific name(s). Regardless, this plant is native to Japan, and I saw it commonly growing up fences. It can also be used as a diuretic.

Fusafujiutsuki / Dense butterfly bush (native)

This lovely plant is actually native to Japan! Unsurprisingly, it is regarded as an ornamental plant, and its flowers feed many butterflies. It has become naturalized in Australia and central and south Europe, but it is regarded as invasive in New Zealand and the British Isles. It is also regarded as invasive in some, but not all, parts of the U.S.

Himetsurusoba / Pink-headed knotweed (native)

It is also called Japanese knotweed. It is used in Chinese medicine to treat kidney stones and urinary tract infections. It is native to Japan and other areas of eastern Asia and Indochina; naturalized in Australia, South Africa, and parts of the Americas; and invasive in the U.K. and Ireland. It is very difficult to get rid of, as it is a highly resilient plant, has an extensive root system, and can regrow from small amounts of roots that are left in the soil. I saw it quite commonly here in Japan, and I think it looks neat, but some gardeners would probably disagree with me!

Ezokanzou / Amur daylily (native)

I got excited when I saw these – they are commonly used in the floral industry, so seeing some growing wild was very exciting! These flowers are actually native to Japan, and their flowers are edible.

Zeniaoi / Common Mallow

This plant is native to Europe, west Asia, and north Africa. It does seem to have escaped gardens in Japan, but I am unsure if it is invasive or not. Also, it is edible.

Seiyou Otogirisou / Chinese St. John’s Wort

Studies have shown that this plant can be used as a treatment for depression. However, it can interfere with many other kinds of prescription medications, so it must be taken with care. It is considered an invasive pest in many countries, and it is harmful to large herbivores such as sheep. In Japan, however, is seems to be naturalized.

Threadleaf Coreopsis

This is a kind of tickseed, different from the lance-leaved tickseed in the previous flower post. Definitely non-native – it’s from the east-central U.S. – but I am unsure if it is invasive (like the lance-leaved tickseed), or even if it has escaped from gardens in Japan yet.

Tsutagarakusa / Coliseum ivy

This plant is native to Southern Europe and was introduced to Japan in 1912. It commonly grows from cracks along walls. Unsure if it is invasive.

Oruraya / Large-flower orlaya (naturalized)

Also known as white laceflower, it’s native to Mediterranean Europe, North Africa, and west Asia. These flowers bloom all summer long. Their only use is ornamental.

Ladies tresses

The genus (Spiranthes) is distributed across the Americas, Europe, Asia, and Australia. I am not sure which of the many species of the genus this is, so there’s no telling where it’s from. It is likely not a native of Japan though – only one species is native to Japan, Spiranthes hachijoensis, and the species was discovered just this year! The new species has a delicate, glass-like appearance, and many specimens were found on Hachijojiima Island. It was hiding in plain sight – many additional specimens were located in parks and pots across the country. I don’t think this is a picture of one, though, meaning that it is some other species of ladies tresses. Also, fun fact – ladies tresses are technically orchids!

Agapansasu / Lily-of-the-Nile

This is a flower that I only spotted growing in gardens, but it looked so pretty that I couldn’t resist including it. These flowers are native to Southern Africa (South Africa, Lesotho, Eswatini, and Mozambique). They are naturalized in some areas (Australia, Great Britain, Mexico, Ethiopia, Jamaica, and more) and invasive in others (such as New Zealand). They don’t seem to have escaped gardens in Japan so far.

Evening primrose (invasive)

Here’s an update from Japanese Flowers: Part 1! I found some common evening primrose (the yellow flowers on the left). I only saw these flowers open at or after sunset. And on the right, a picture of the pink evening primrose, spotted in Japan (instead of just being shown in a stock photo)! The pink evening primroses open earlier. I was very excited to see the pink evening primrose in person here (though I shouldn’t be, because it is invasive…)

Here’s a direct link to Flowers: Pt. 1. The first blurb on primroses is at the end of the post. https://www.melissastraveladventures.com/2023/04/24/japanese-flowers-part-1/

Yanagi hanagasa / Purpletop vervain (invasive)

Purpletop vervain has spread through most of Japan. It has been known to be in Japan since the 1940s, but its true date and origin of introduction is unknown. However, it was likely introduced as an ornamental plant. It is native to tropical South America.

Cheisuto tsurii / Chastetree

This plant is native to the Mediterranean. The fruits are edible. It is used as an ornamental plant and is known to attract butterflies. In addition, there is some evidence that its berries can help with menstrual problems such as PMS, but more research should be done to confirm this.

Oshiroibana / Common four o’clock (invasive/naturalized)

I couldn’t find a consensus on when this plant entered Japan, or if it is considered invasive or naturalized. They are from tropical America, such as Peru. The name, meaning white powder flower, comes from the seeds. When you crack open the black seeds, a white powder comes out. I spotted a lot of these in Minamiboso, but I have also seen them elsewhere. The flowers open from late afternoon to dusk and close in the morning, which is where their name comes from.

Himejo-on / Daisy fleabane (invasive)

In Japanese Flowers: Part 2, we saw the Mexican fleabane. Now, we meet the daisy fleabane. Also invasive, it blooms (or perhaps its flowers persist) later in the year than the Mexican fleabane. It is native to North and Central America.