Shrub · Berberidaceae
Oregon Grape
Mahonia aquifolium
Give it shade and a little shelter from winter wind, and Oregon grape will thank you with yellow spring flowers and blue-black berries.
Partial shade
Every 7–14 days
USDA 5–8
3–6 ft · 0.9–1.8 m
Overview
Oregon grape is an easygoing evergreen shrub from the Pacific Northwest, and its glossy holly-like leaves are its calling card, flushing bronze in the cold and settling back to a deep green come spring. Despite the name it sits in the barberry family rather than with the grapes, and it borrows its common name from the clusters of blue-black berries that ripen toward the end of summer. If you want something that looks good in every season without much fuss, this is a kind plant to begin with.
Do not expect a sprint, because this shrub takes its time, easing up to 3 to 6 feet tall over years rather than in a single season. It travels underground on stolons and sends up suckers that gradually weave into a low, colonizing patch. That gentle spreading makes it a lovely groundcover for a shaded bank, and if you would rather it stayed put, all it takes is pulling the odd stray shoot now and then.
Early spring is when it really shines, offering up dense clusters of bright yellow flowers that welcome the first bees, and later the tart berries that birds enjoy and people turn into jelly. Hardy right down to -20°F (-29°C), it copes with a rough winter without complaint, as long as you keep it clear of drying wind.
Care
The short version: give it a home in partial shade with some shelter from winter wind, in moist, acidic, well-drained soil, and water it faithfully until it settles in. From then on it asks for almost nothing beyond a friendly spring tidy-up.
Light
Oregon grape is happiest in partial to full shade, and that is where its leaves stay glossy and green. It will put up with full sun, but the foliage tends to bleach and scorch there, especially over winter, so a spot with some overhead cover really does keep it looking its best.
Water
Keep the soil evenly moist through the first season or two while the roots are finding their way out. Once it is established the shrub takes dry spells in stride, so you can let the top inch dry and water just every 7 to 14 days. The one thing it truly won't forgive is sitting in standing water.
Soil
Settle it into moist, rich, acidic, well-drained ground somewhere in the 5.0 to 7.0 pH band. It really dislikes alkaline, compacted, or soggy soil, and adding lime is the surest way to bring on the yellow leaves it is prone to, so it is best avoided.
Temperature
This is a wonderfully cold-hardy shrub, at ease anywhere from about -20°F to 90°F (-29°C to 32°C). A hard winter really doesn't trouble it, provided you keep it out of biting wind, because it is the wind that scorches the leaves, not the cold on its own.
Humidity
Everyday outdoor humidity suits it just fine, so there is no number you need to chase. Good air movement matters far more than moisture in the air here, since crowded, still foliage is what tends to invite leaf spot and rust.
Feeding
One spring feed is all it really wants, so there is no need to overthink it. Reach for a balanced or acidifying shrub fertilizer, and switch to an acidic formula if you notice the leaves yellowing from high-pH chlorosis.
Pruning
Prune after flowering to tidy its shape, or to cut a leggy plant back hard for a fresh flush of growth. Take out any dead, damaged, or winter-burned stems while you are at it, and pull the odd unwanted sucker as it appears to keep the patch where you want it.
Repotting
Grown in the ground it never needs repotting at all, and in a container it is content to be left alone for years. Only move it up when you see roots circling the pot or the soil starts drying out far too quickly.
Size & spacing
Look for a mature plant of about 3 to 6 feet (91 to 183 cm) tall with a spread of 20 inches to 5 feet (51 to 152 cm) as the suckers gradually fill in. Give it room to spread and enjoy the colony, or simply trim the edges back each year to keep it neat.
When to plant
Oregon grape keeps its own gentle rhythm through the year, and it is happy to let you follow along. Plant it in spring or fall while the soil is easy to work, look for yellow flowers in early spring, and wait for the blue-black berries to ripen from late summer into early fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall
- Harvest: Yellow flowers in early spring; blue-black berries ripen by late summer to early fall
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
Nearly every hiccup with Oregon grape turns up on the leaves, and more often than not it comes down to where the plant is sitting rather than any pest. Read the foliage and the answer is usually right there. Find the match below, sort out the site first, and you will rarely need to reach for a spray.
Brown, scorched leaf edges that worsen over winter
If the leaf edges go brown and crisp, take heart, because this is winter leaf burn and it is a siting issue you can fix, not a sign you have killed the plant. It happens when winter sun and dry wind pull moisture from the leaves faster than the cold roots can send it back up, and harsh summer sun on an open spot can do the same. Move it somewhere shaded and sheltered, mulch and water it well before winter sets in, and trim off the tired foliage in spring when the fresh growth arrives.
Fix:
- Site in partial to full shade with shelter from strong and drying winter wind
- Mulch and keep soil evenly moist going into winter
- Prune out badly burned foliage in spring as new growth emerges
Yellow leaves with veins that stay green
When a leaf yellows but its veins stay a clear green, you are seeing iron chlorosis, and the good news is that it points to the soil rather than to anything you did wrong. The roots simply cannot draw up enough iron because the ground has drifted too alkaline. Start with a soil test, then bring the pH down gently over time with elemental sulfur or an acidifying fertilizer, and lean on chelated iron when you want the green back sooner.
Fix:
- Test soil pH
- Lower pH and acidify with elemental sulfur or an acidifying fertilizer
- Apply chelated iron for quick correction
Spots or orange rust pustules on the foliage
Small spots or orange-to-brown pustules on the leaves are the work of leaf spot and rust fungi, and they tend to settle in when plants sit crowded together in damp, still air. Nothing here is a crisis. Pluck off the marked leaves and bin them, then thin the plant a little so air can move through and the foliage dries quickly after rain. Save a labeled fungicide for the rare year when an outbreak truly gets away from you.
Fix:
- Remove and dispose of affected leaves
- Improve air circulation and avoid overhead watering
- Apply a labeled fungicide if infection is severe
Toxicity
This is a friendly plant to share your garden with, though it is not quite a free-for-all. The cooked berries are good to eat, while the roots and stems carry berberine, a bitter compound that can upset a stomach if a pet or person swallows much of it. In truth the spiny leaves cause more everyday grief than the chemistry does, so slip on gloves whenever you handle it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock
Safe for
People · Birds
Cats Mild
The roots and stems hold berberine, so if a cat really chews on them it might drool, be sick, or have runny stools. A quick nibble of a leaf is almost never a problem; the upset only shows up when a curious cat swallows a proper mouthful.
Dogs Mild
A dog that gnaws the stems or roots can come away with a queasy stomach and a spell of diarrhea from that same berberine. How rough it gets tracks with how much went down, and most dogs come right on their own.
Horses Caution
Horses usually walk past the prickly leaves without a second look, though the berberine in the woody parts could still unsettle the gut if one grazes a fair amount. Keep it out of reach where pastured horses browse and you have nothing to worry about.
Rabbits Caution
A rabbit is little enough that even a small helping of the bitter, berberine-laced foliage can upset its digestion. It is kindest not to offer the plant as forage at all.
Livestock Caution
Cattle, goats, and sheep normally leave the spiny leaves well alone, but a good mouthful of stem or root could still bring on a bit of digestive upset. In practice, stock rarely go looking for it.
Birds Safe
Wild birds happily feast on the ripe blue-black berries and carry the seed off unharmed. That partnership is one of the ways the shrub finds new ground.
People Berries safe when cooked
Once the tart berries are cooked down into jelly or wine they are lovely to eat, so the fruit is perfectly safe for people. Just leave the roots and stems be, since the berberine in them can upset the stomach if you eat much.
The glossy, holly-like compound leaflets have stiff spine-tipped teeth that can prick or scratch skin; wear gloves and use care when pruning or handling.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Most gardens simply grow the straight species and do well by it, but a couple of named selections are worth hunting down when space is tight or you want more flowers.
'Compacta'
A friendly dwarf that stays around 2 to 3 feet tall, so it slips neatly into tight corners and knits together beautifully when you mass it as a low groundcover.
'Apollo'
A low, spreading pick that gives you a generous flush of yellow flowers over a neat, dense habit.
How to propagate
Oregon grape hands you three ways in, from quick to slow, so pick whichever suits your patience. Splitting off the rooted suckers is the gentlest place to start, while cuttings and seed both reward a bit of waiting.
Stem cuttingsModerate
Late fall to winter, after some cold exposure · Several weeks to months to root
Take semi-hardwood cuttings in late fall or winter, once the wood has felt a touch of cold, and dip the cut ends in rooting hormone to help them along. Settle them into a moist, well-drained mix and then simply be patient, because roots can take several weeks to a few months to appear, and that is completely normal.
DivisionEasy
Spring or fall · One growing season
This is the easiest way in, and a lovely place to start. The shrub creeps outward on stolons to form colonizing clumps, so in spring or fall you can lift it, cut away the rooted suckers, and tuck them straight back into the ground. Each piece will find its feet over one growing season.
SeedModerate
Sow stratified seed in fall or after cold stratification · One or more years; seed is slow to germinate and reach size
Seed is the slow and gentle route, and worth trying if you like a project. Clean the pulp from ripe berries and either sow in fall or give the seed a cold stratification first, since it simply won't wake up without that chill. Expect a year or more before the little seedlings put on any real size, and let that be part of the fun.
Myths
Oregon grape berries are poisonous because they look like holly or barberry fruit.
It is easy to be fooled by how they look, so don't worry. The blue-black berries are far too tart to enjoy straight off the shrub, but simmer them into jelly or wine and they are a treat, and the plant is listed as non-toxic to cats, dogs, and horses. The fruit is safe; it is only the bitter roots and stems worth keeping away from curious mouths.