Vaccinium

( vacks - IN - ee - um )

At-A-Glance Information

This genus of evergreen and deciduous shrubs will attract birds and butterflies to your garden, and are excellent ornamental shrubs. They produce clusters of flowers in spring that are followed by edible berries, and are great for woodland gardens. Species of this genus include berry favorites like Blueberry, Hackberry, Cowberry, and Cranberry. Some trail along the ground, and others form sprawling shrubs.

vaccinium Species and Varietals

The genus Vaccinium includes many species divided into a few sub-genera, which are then divided into sections, and is a member of the plant family Ericaceae. . The subgenus Oxycoccus includes cranberries and a mountain blueberry species, and the subgenus Vaccinium includes all other species in the genus. The genus was first formally described, as many others were, by Carl Linnaeus in his 1753 in his publication Species Plantarum. The most ideal growing zones for Vaccinium vary, depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Vaccinium macrocarpon (Cranberry)
This species is an evergreen native to the northeastern United States and eastern areas of Canada, and grows well in zones 1-6 and 17. It reaches just 2-6 inches tall and spreads and roots from stems indefinitely. Leaves are narrow and dark green and turn colors in wintertime. Flowers are small and pinkish, and berries are tart and red, produced in fall. Cranberry makes a great small-scale groundcover in full sun. Provide ample water; these shrubs may be small, but they are quite thirsty.

Vaccinium moupinense
This species grows in zones A3, 2-7 and 14-17 and is native to western China. It forms an evergreen, compact shrub to 1-2 feet tall and wide. New growth is reddish and matures to green. Fall foliage is dark red. Flowers are reddish-brown and followed by tart, purple-black fruit.

Vaccinium ovatum (Evergreen Huckelberry)
This species is best in zones 4-7, 14-17 and 22-24, and is native to the Pacific coastal region. It has an erect habit to 2-3 feet tall and wide when grown in sun, 8-10 feet tall and wide in shaded areas. It has dark green leaves that are bronze or whitish when new. Pink or white flowers are followed by black berries that are great for jellies, jams, and syrups. Great as a hedge or when grown in containers. Cut branches are used in flower arrangements. The plants in this species need moderate to regular water for best performance.

Vaccinium parvifolium (Red Huckleberry)
This deciduous shrub is native to the Sierra Nevadas and Coast Ranges from Northern California up to Alaska. It is a slow grower, topping out at 4-12 feet tall and 6 feet wide. Branches have a cascading habit and leaves are light green. Bright red berries follow green to white flowers, and are used in jams, jellies and pies. Needs partial to full shade and regular to moderate water to fruit well.

​Vaccinium vitis-idaea (Lingonberry, Cowberry, Foxberry)
This species is evergreen and grows well in zones 2-7 and 14-17. It is native to Europe and slowly reaches a foot tall, spreading widely by rhizomes. These shrubs enjoy highly organic and mulched soil. Leaves are glossy and dark green, and flowers are white-pink and are followed by sour red berries. They are great for preserves and syrups. Do not use potassium fertilizer; provide ample amounts of water. Likes partial to full shade but can handle sun in cool-summer areas.

Vaccinium vitis-idaea minus (Dwarf Lingonberry)
Zones A1-A3, 1-7 and 14-17. This is a cold-hardy variety from the arctic regions of North America, and has smaller leaves than other species. Great for rock gardens and for container plantings.

Caring for and pruning vaccinium shrubs

​These shrubs generally thrive in full-sun conditions, but they are naturally woodland plants, and some species grow larger in shaded conditions. Check species' unique sun requirements before planting. As a rule of thumb, most require about 6-8 hours of sun each day. Vaccinium shrubs prefer acidic soil with a pH of between 4.0 and 5.5. Amend soil with a peat moss or acidic compost to maintain a desirable pH level. These shrubs do very well in sandy loam soils. Keep soil consistently moist; especially during the active flowering and fruiting seasons. Mulch around the base of the plant after installing to increase soil moisture retention and suppress weed growth. Vaccinium shrubs are generally cold-hardy plants; many grow up the Northern California Coast and some species can even thrive in places like Alaska. In fact, most species need a cold snap to produce a good yield. Use a fertilizer specifically made for acid-lovers, and apply in early springtime before new growth pops out. Pruning Vaccinium is relatively straightforward; simply remove dead, damaged or diseased growth, and trim to encourage a bushier growth. Pruning activities are best completed in late wintertime or early springtime. 

Many Vaccinium species can be grown in containers; this is an especially useful tool if you have alkaline soil. Make sure to use an acidic potting mix and choose a container with good drainage. The amount of root space that container-grown Vaccinium shrubs need varies depending on the species. As a general rule of thumb, larger plants will have larger root systems and will therefore need larger containers to grow in. Most species will need a container that is, at minimum, 2 feet deep and 2 feet wide. 

Harvesting Vaccinium
Because there are so many different species and varieties in this genus, harvesting methods and timing varies. Generally, you'll want to harvest your berries when they have fully attained their final color. The berries at this time will be very slightly squishy, and deep in color. Vaccinium shrubs are usually ready for harvesting between June and August, but it does vary. Because the berries are so small and there are so many of them, it may be simpler to use a harvesting tool called a berry picker (essentially a fork attached to a bucket). Examples can be found by following this link. Once the berries are off of the plant, store them in the refrigerator. They will stay good for about 10-14 days. if you're going to freeze your blueberries, do not wash them first. If you harvest your berries before they are fully ripe to combat birds and other hungry animals eating all of them, they can be placed in a paper bag and stored in a cool, dry, dark place to ripen. A banana or apple can be added to the bag as well to speed up the process; the ethylene released from the fruit will ripen the berries.

Propagation

Vaccinium can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Vaccinium by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. 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.
  2. In March, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 12-30 inch hardwood portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. The chosen branch should be close to the base of the shrub, and have no fruit or buds on it. After you've taken your cutting, you'll want to break it into smaller portions. Make cuts to create 3-4 inch long pieces, each cut should have its base be just below a leaf node. Then, make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots. 
  4. 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, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Vaccinium 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, newspaper, ground sphagnum moss, sand, potting soil and a pot or tray filled with finely ground sphagnum moss. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Extract your seeds. The seeds in most species are small, soft, and contain the same nutrients as the fruit itself. Fully ripe berries contain up to 50 very tiny seeds each. To remove them from the fruit flesh, the berries can be blended in a blender or squished. If processing in a blender, put the berries in and then fill with water so that 3/4 of the blender is filled. Blend, and then let it sit for at least 5 minutes. Pulp will be suspended in the water, and the seeds will sink to the bottom. Pour off the pulp, add water, and stir. Let it sit for another 5 minutes. Pour off the pulp. Continue this process until all of the pulp is removed, and then collect your seeds. If using the squish method, mash your blueberries, and then place them in a sealable mason jar filled 3/4 of the way with water. Follow the same procedure as with the blender method. After seeds have been removed, set them out to dry on a towel.
  3. Prepare your sphagnum moss pot or tray, and water to ensure that good drainage is occurring. Place your seeds on your prepared pot or seed tray and then lightly cover with more ground sphagnum moss. Cover them with newspaper and water with your spray bottle when the planting medium dries. 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 30 days from sowing. Once you begin to see seedlings sprout and they are 2-3 inches tall, transplant them to their own individual 3-inch pots, filled with an equal parts peat moss, sand and potting soil. 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. The seedlings are very delicate, so take care when completing this process.
  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.
  5. Continue to care for your propagation, covering it in cool weather and providing adequate water and nutrients for healthy growth. Plants will produce a few berries after two years, and in the years that follow, production will rise as the shrub really gets established in the garden.
Vaccinium seeds are very small and are contained inside the fruit.
Vaccinium seeds are very tiny.

Problems and Pests

Vaccinium shrubs are susceptible to problems with the following pests and diseases:
  • Citrus Thrips
  • Katydids
  • Light Brown Apple Moths
  • Masked Chafer (White Grub)
  • Pacific Flatheaded Borer
  • Spotted-Wing Drosophila
For more information on these pests, including how to eradicate them, see the following links:

Gallery

Use Vaccinium shrubs as dual-purpose plantings; they can be very productive low hedges.
Vaccinium grows well in containers.
Use Vaccinium shrubs to add interest, edibility, and texture to mixed beds.

Videos

All about Vaccinium shrubs.
How to care for Vaccinium.
All about Blueberry plant cultivation.
Growing Blueberries in containers.

Resources

Growing Blueberries from Seed
Blueberries (Vaccinium)
Deciduous Shrub Cutting Propagation:: Blueberry Bush
Wikipedia: Vaccinium
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 644, Vaccinium
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