Frangula

( frang - OO - luh )

At-A-Glance Information

Frangula is a group of evergreen and deciduous shrubs and trees commonly known as Buckthorn. Their berries will attract birds to your garden; and they can provide lovely mass and texture to landscapes. Use Frangula shrubs in woodland areas, as part of shrubberies, or as specimen plants in mixed beds. 

Frangula Species and Varietals

The genus Frangula includes around 50 distinct species of flowering shrubs and small trees, and is a member of the plant family Rhamnaceae. They are closely related to Rhamnus. These plants were at the height of their usefulness during the 15 through 19th centuries when their wood was used to make charcoal for gunpowder manufacture. Frangula growing zones vary by species; for more information, see the descriptions below. To find your zone, click here: Zone Map.

Frangula californica (Rhamnus californica) (Coffeeberry)
Grows best in zones 3a-10, 14-24, H1 and H2. This shrub is native to California, southwest Oregon, and Arizona. It gets 3-15 feet tall and 8 feet wide. Leaves are dark green to yellowish-green, and are pale underneath. Berries ripen from green to red to black. This shrub will attract bees, and is tolerant of pruning and shaping. Full sun or partial shade is preferred, but it is not picky about soil.

Frangula purshiana (Rhamnus purshiana) (Cascara, Chittam Bark)
This deciduous shrub grows best in zones 1-9 and 14-17. Native from Northern California to British Columbia and Montana. Gets to 20-40 feet tall and 10-30 feet wide. Bark is smooth gray or brown, and has medicinal value. Dark green leaves turn to yellow foliage in fall, and black berries appear in fall. Can take full sun to dense shade, and moderate to regular water. 

Caring for and pruning frangula shrubs

Plant Frangula shrubs in well-draining soil in full sun to partial shade. Frangula prefers soil that is slightly alkaline and kept consistently moist, though it will tolerate dry and poor soil as well. Fertilize in spring and summertime with a balanced, slow-release fertilizer about once a month, and prune only to remove dead, damaged or diseased branches and foliage. 

Propagation

Frangula is most easily propagated from seed. To propagate your shrub, follow the instructions below:

Propagating Frangula by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a strainer, a paper towel, a container for storing your seeds, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows. 
  2. Harvest your seeds. The seeds on Frangula shrubs and trees are contained inside the fruits produced in fall. They should be ready to harvest in early to mid-winter. Remove the berries from the shrub at this time, and take the seeds out. Use a strainer to wash the remaining fruit flesh off of the seeds, and set them out on a paper towel to dry. Once they are dried, place them in a container in a cool, dry, dark place for storage until you are ready to sow.
  3. In fall, water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes around 45 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  4. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Problems and Pests

Frangula shrubs have no serious pest or disease issues, but under poor conditions can suffer from the following issues:
  • Cercospora
  • Phylosticta
​For more information on these issues, see the following links:
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Gallery

Pair Frangula shrubs with other shrubs of differing foliage colors; they will add great texture and color with their berries.
Frangula shrubs have beautiful, shiny green foliage and berries that will attract birds to your garden.
Pictured here is a Rhamnus shrub, a close relative of the Frangula genus.

Videos

An informational video on California Coffeeberry.
Identifying Frangula shrubs.

Resources

Frangula - Landscape Plants
Wikipedia: Frangula
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 326, Frangula
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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