Orchids on the Rocks

Orchids on the rocks? No, it’s not another post about ice cubes or climate change. Instead, it’s about orchids which actually grow on rocks. Attached by their roots, orchids may wedge into stony crevices or hang off sheer mountain cliffs. Many orchids which are air plants can affix to both trees __and rocks. The first three photos show a few species which can grow this way: a Dendrobium, a Laelia, __and a Sarcochilus.

Dendrobium kingianum, orchid species, sometimes grows as a lithophyte, Pacific Orchid Expo 2016, San Francisco, CaliforniaLaelia crispata, orchid species with bright yellow flowers, rupicolous Laelia, lithophyte, Pacific Orchid Expo 2011, San Francisco, CaliforniaSarcochilus hartmanii, Australian orchid species, grown outdoors in San Francisco, California

Plants which grow on rocks are called lithophytes. Gardeners may also hear the word rupicolous, which has the same meaning.  Lithophytes in the orchid family include some Lady Slippers, Dendrobiums, Sarcochilus, Cattleyas, Bulbophyllums, Oncidiums, Angraecums, and many more. Their roots cling to rough stone surfaces, and expand into cracks and crevices to help secure themselves. They may live in pockets of soil or rotting leaves which provide them with nutrients. Some of the pictures below show how their white roots attach to rocks.

Orchid growing attached to rock, lithophyte, Vallarta Botanical Gardens, Puerto Vallarta, MexicoEpidendrum orchid attached to rock, lithophyte, Akatsuka Orchid Gardens, Volcano, HawaiiClose up of orchid roots of Epidendrum attached to rock, lithophyte, Akatsuka Orchid Gardens, Volcano, Hawaii

Epidendrum roots attached to rock, lithophyte, Kula Botanical Garden, Maui, HawaiiOrchid growing in lava rocks, near MakuOrchid growing in moss-covered rocks, lithophyte, Vallarta Botanical Gardens, Puerto Vallarta, Mexico

Keeping orchids as lithophytes can be tricky. Rock can quickly heat up in direct sun, and flat areas may not drain well, so it’s important to pay careful attention to light, water, and humidity. The standard advice is to grow lithophytes like air plants, keeping them in well-drained pots with bark or moss, rather than risking them on stone. For the adventurous, Growing Orchids in Your Garden by Robert G.M. Friend has a chapter on lithophytes, including which varieties work best.

Orchid growing attached to large rock, lithophyte, Foster Botanical Garden, Honolulu, HawaiiOrchid growing attached to rocks, lithophyte, Hawaii Tropical Botanical Garden, Papaikou, Big Isl , HawaiiOrchid growing attached to bricks, lithophyte, Montreal Botanical Garden, Montreal, Canada

For more photos of orchid on the rocks, check out this blog post about plants in Cambodia.

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