Crab Claw: The Parasitic Plant on Ancient Tea Trees

Sometimes in photos of ancient tea trees you'll see clumps of small green plants hanging from the branches, flat and strung together joint by joint, looking a bit like coral, or like crab legs. People on the tea mountains call it "pangxiejiao" (螃蟹腳, crab claw). Online it's often sold together with ancient-tree pu'er, which leads many people to think it's a kind of tea.

What Is Crab Claw?

Crab claw is a parasitic plant, generally considered to belong to the genus Viscum (mistletoe) in the Santalaceae family (formerly classified in Viscaceae); common accounts point to Viscum articulatum (flat-stemmed mistletoe) or something similar, while some sources consider it a close relative in the same genus. Plants of the genus Viscum share one trait: they don't root in the soil but push haustoria into the host tree's branches, taking water and nutrients from the host, while also having green stems of their own that photosynthesize; they're "hemiparasitic" plants.

Viscum articulatum has flat stems joined segment by segment, and its leaves are so reduced they're almost invisible, so the whole plant looks like strings of flat green segments, which is where the name "crab claw" comes from. It's found in Yunnan, Guangxi, Guangdong, and Southeast Asia, on many hosts: persimmon, oak, maple, and mulberry trees can all carry it.

Is Crab Claw Tea?

No. Crab claw and the tea plant are entirely different plants; it simply grows on tea trees. It doesn't belong to the tea family (Theaceae), nor is it the tea tree's branches, leaves, flowers, or fruit. Picked and dried, it's the dried stem of a parasitic plant, not tea leaves.

Pu'er's national standard specifies that pu'er is made from sun-dried Yunnan large-leaf tea, and crab claw isn't part of that.

Why Is It on Ancient Trees?

It's not that it grows "only" on ancient trees, but that it's easier to see on old tea trees. There are roughly a few reasons:

• Time: Parasitic plants spread their seeds through birds that eat their fruit, and old trees that have stood on the mountain for a long time have more chances of being "sown."
• Bark and branches: Old trees have rough branches with many forks, where seeds easily lodge and germinate.
• Environment: Ancient gardens are mostly in forest, humid, and sprayed little, which suits parasitic plants.
• Management: Terrace gardens are pruned every year, so parasitic plants are cut off before they can grow.

Because of this, there's a saying on the tea mountains that "a tea tree with crab claw is at least a hundred years old," but that's just experience and can't be used as a basis for judging tree age.

Crab Claw's Effect on Tea Trees

Parasitic plants divert water and nutrients from their hosts. A little parasitism has little effect, but too much can weaken or kill the affected branches. Tea farmers' attitudes are split: some see it as a symbol of old trees and keep it deliberately; others remove it to protect their trees. In recent years, as crab claw has been hyped, some ancient tea trees have been over-climbed and over-picked, which actually does harm.

Can Crab Claw Be Brewed with Pu'er?

You'll often see "ancient-tree pu'er + crab claw" combinations on the market; be clear that this is pu'er plus another plant, no longer plain pu'er. In Taiwan, tea is ordinary food, and other plants used in food have their own regulations and labeling requirements. Our suggestion is to drink pu'er as just pu'er; if you're curious about crab claw, think of it as a bit of knowledge about the ecology of ancient tea trees.

What Crab Claw Tells You About Ancient Gardens

Crab claw, mosses, ferns, and orchids, these epiphytes and parasites growing on ancient tea trees show that the garden is humid, the forest structure intact, and human disturbance low. It's a scene unique to understory ancient gardens; see Understory Tea and the Management of Ancient Tea Gardens. The definition and identification of ancient trees are in Ancient Trees, Large Trees, and Terrace Tea.

How to Spot It on a Tea Mountain

If you get the chance to visit an ancient garden in Yunnan, here's how to recognize crab claw:

• Location: Growing on the tea tree's branches, not on the ground;
• Appearance: Strings of green or yellow-green flat stem segments, hanging or clustered, with no obvious leaves;
• The join: Where it meets the tea branch there's often a swollen knot, where its haustoria enter the host;
• Season: Visible year-round, more yellowish in the dry season.

When you see it, take a photo as a keepsake; don't climb or break it off, as old tea tree branches are more fragile than you'd think.

FAQ

What is crab claw? A parasitic plant growing on the branches of ancient tea trees and other trees, in the genus Viscum (mistletoe) of the Santalaceae family, with flat, jointed stems shaped like crab legs.

Is crab claw tea? No, it's a different plant that simply parasitizes tea trees.

Is a tea tree with crab claw always an ancient tree? It's more common on old trees, but it can't be used to judge tree age.

Can crab claw be brewed with pu'er? Then it becomes pu'er plus another plant, no longer plain pu'er; we suggest drinking pu'er on its own.