Blue holly
Ilex x meserveae · Aquifoliaceae
The holly of Christmas cards for cold climates: glossy, spiny, blue-green leaves on purple stems, and bright red berries on female plants when a male is nearby.
- Size
- 8 ft tall, 6½ ft wide
- Zones
- 5 to 7
- Light
- Full sun to part sun
- Flowers
- Grown for its leaves
- Pets
- Toxic (mild)
- Job in a bed
- Anchor
A bed built around blue holly
The planner designed this bed around blue holly when this page was made: a 16 × 8 ft (4.9 × 2.4 m) English border in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why blue holly stands where it does.
The plants
- 1 Blue holly × 1, blue-green leaves
- 2 Bloody cranesbill × 7, pink
- 3 Leadwort × 19, blue
- 4 White mugwort × 4, cream
- 5 Siberian iris 'Caesar's Brother' × 3, purple
- 6 Beardtongue 'Husker Red' × 5, white
- 7 Goldenrod 'Golden Fleece' × 3, yellow
- 8 Tulip 'Apeldoorn' × 8, red
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
- The bed's only structure. Shrubs and grasses keep their shape when the perennials die down, and it is the only one here.
Why here
- Anchors a back corner. At 8 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to white mugwort (5 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A shrub is seen as an object, and needs clear ground around it.
Why now
- Here for its leaves, all year. They cover the 17 weeks between early March and late November when nothing on the plan is in flower.
- The only leaves in winter. From November to March it is what there is to look at.
Planned as an English border: 7 of the 8 groups (88%) are drifts, longer along the bed than they are deep. The bed is tied together by its repeats: three kinds come round again along it, among them leadwort and bloody cranesbill. Low plants run along 97% of the front edge: bloody cranesbill and leadwort.
The planner's own design check: 10 Excellent, 5 Good, 1 Satisfactory, 1 Needs revision. Its weakest point is height and scale: Heights average about 12 in at the front, 24 in in the middle and 4½ ft at the back. Along the back row the heights step up and down, between 3½ ft and 8 ft, and no two neighbours are the same height. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where blue holly goes in a border
At 8 ft it belongs at the back of a bed. In the planner's ten height classes it is super tall (over 6½ ft).
Its job: anchor. A shrub that gives the bed permanent structure. Planted singly, as soon as the front edge is laid; everything else is arranged around it.
English holly is not hardy in the North; this is. Plant one male for every few females, or there will be no berries.
- Evergreen hedges and screens in cold climates
- Winter berries
- Cut branches for decoration
What to plant with blue holly
Plants recorded as good partners for it, and what each pairing does:
- Rhododendron 'PJM': adds the flowers, late April to mid May; low enough (5 ft) to stand in front of it.
- Dwarf Korean lilac 'Palibin': adds the flowers, late May to early June; low enough (5 ft) to stand in front of it.
- Cranesbill 'Rozanne': adds the flowers, early June to early October; low enough (18 in) to stand in front of it.
Questions about blue holly
Does blue holly need sun or shade?
Blue holly grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells.
What zones does blue holly grow in?
USDA zones 5 to 7. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Above zone 7 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should blue holly be planted?
5 ft (150 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 6½ ft (200 cm), so a group knits into one patch.
It grows 8 ft (250 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many blue holly plants do I need?
Usually one. At 5 ft (150 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 5 ft apart: three plants for a 10 ft run.
In the bed above, the planner used one in one group.
Is blue holly poisonous to dogs and cats?
Yes: mild toxicity to people, dogs, cats and horses. The berries and leaves cause vomiting and diarrhoea if eaten.
Rated from NC State Extension. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like blue holly?
These come closest to doing what blue holly does, and no toxicity is recorded for them:
- Variegated red twig dogwood: the same job in a bed; 20 in shorter, not evergreen.
- Mugo pine: the same job in a bed; 3½ ft shorter, 12 in wider.
- Alpine currant: the same job in a bed; 3½ ft shorter, 20 in narrower.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat blue holly?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What does blue holly look like in winter?
Blue holly keeps its blue-green leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone. It is grown for winter berries as well.
Is blue holly good for bees and butterflies?
Blue holly is visited by pollinators, specialist bees and songbirds.
More Ilex
- Blue holly 'Blue Princess' Ilex x meserveae 'Blue Princess'
- Burford holly Ilex cornuta 'Burfordii'
- Dwarf yaupon holly Ilex vomitoria 'Nana'
- Inkberry Ilex glabra
- Inkberry 'Gem Box' Ilex glabra 'SMNIGAB17' (Gem Box)
- Inkberry 'Shamrock' Ilex glabra 'Shamrock'
- Japanese holly 'Helleri' Ilex crenata 'Helleri'
- Japanese holly 'Sky Pencil' Ilex crenata 'Sky Pencil'
- Japanese holly 'Soft Touch' Ilex crenata 'Soft Touch'
- Winterberry Ilex verticillata
- Winterberry 'Berry Poppins' Ilex verticillata 'FARROWBPOP' (Berry Poppins)
- Winterberry 'Red Sprite' Ilex verticillata 'Red Sprite'
- Winterberry 'Winter Red' Ilex verticillata 'Winter Red'
In these guides
Every fact on record
- Type
- Shrub
- Size
- 8 ft (250 cm) tall, 6½ ft (200 cm) wide
- Plant
- 5 ft (150 cm) apart
- Height class
- Super tall (over 6½ ft)
- Place in the bed
- Back
- Flowers
- None: grown for its foliage
- Leaves
- Medium texture, evergreen; blue-green
- Shape
- Rounded, clumping
- Hardy in
- USDA zones 5 to 7
- Light
- Full sun, part sun
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Aquifoliaceae
- Attracts
- Pollinators, specialist bees, songbirds
- Stands up to
- Deer
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.