Cascara Sagrada

Frangula purshiana

tree

Cascara sagrada (Frangula purshiana), the "sacred bark," is a Pacific Northwest understory tree or large shrub, 15 to 30 ft tall, of moist, shady forests and streambanks from British Columbia to California. Its smooth gray bark comes with an absolute rule: the fresh bark is harshly griping and must be dried and aged for about a year (or heat-cured) before use, which mellows it. It is grown for that bark, harvested and then aged, and as a quiet, shade-tolerant native tree with berries that feed birds. It is easy in cool, moist, shaded ground.

✅ Plant alongside

Good neighbors that attract beneficial insects or deter pests

• Salal — A native Northwest evergreen shrub for the shaded, moist understory alongside cascara
• Fern — A natural woodland companion for the cool, damp, shady ground
• Oregon Grape — A shade-tolerant native shrub that shares the same forest-floor conditions

🛡️ Pest & disease prevention

Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide

• Aphids →

  Occasional colonies on new growth; rinse off and let predators work

• Leaf spot →

  Minor fungal spotting in damp shade; rake litter and allow airflow

• Scale →

  Wipe or treat small infestations with horticultural oil; rarely serious

🌾 Harvest & storage

Strip the bark in spring or early summer when it lifts easily, taking it from branches or coppiced stems rather than felling the tree, which then resprouts. Here is the essential step: dry and age the bark for at least a year before any use, because fresh cascara bark is violently griping; aging (or gentle heat-curing) mellows it. Dry it completely and store it a full season before use. The berries are not eaten.

🥗 Nutrition & benefits

Cascara sagrada is grown for its bark, which has a strong purgative effect and must be dried and aged about a year before any use, as fresh bark causes severe cramping; the berries are not a food. In the garden it is a useful, easygoing native understory tree for shade and a good bird plant, asking little once established.

⚠️ Toxicity & safety

Cascara is grown as an ornamental and is safe to handle, but it is a powerful laxative and must not be eaten casually. The bark's anthraquinones make it a strong purgative, and FRESH bark causes violent cramping, nausea, and vomiting - it must be dried and aged for about a year (or heat-cured) before any use. The berries are not a human food. The FDA withdrew cascara as an over-the-counter laxative ingredient in 2002 for lack of proven safety data. Treat it as a medicinal, not a snack.