Western mock orange

Sun

Full sun to partial shade; flowering is strongest with at least 6 hours of direct sun.

Water

Water regularly while establishing. Once established, it tolerates seasonal drought; water deeply during prolonged dry spells, especially in hot inland gardens.

Soil

Well-drained soil, from sandy or stony ground to loam and drained clay; tolerates mildly acidic to alkaline conditions. Avoid persistently waterlogged sites.

Height

6-10 ft (1.8-3 m)

Spread

6-10 ft (1.8-3 m)

Flowers

Late spring to early summer; fragrant white flowers with four petals and yellow stamens.

Foliage

Opposite, oval to pointed green leaves, often toothed toward the tips; autumn colour is usually muted yellow.

Growth

Moderate to fast, depending on moisture and growing conditions.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Wildlife
• Low allergen
• Fragrant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.6 ft (0.5 m)

2. After 1 year

   3 ft (0.98 m)

3. After 2 years

   5 ft (1.5 m)

4. After 3 years

   6 ft (1.9 m)

5. After 5 years

   8 ft (2.4 m)

   full size

About 4 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US and Canada

Growth rate

Fast

• Water deeply during dry weather for the first two growing seasons, allowing the surface soil to dry between waterings.
• Apply 2-3 in (5-8 cm) of organic mulch over the root area, keeping it clear of the stems.
• In poor soil, add a thin layer of compost in spring; avoid heavy nitrogen feeding, which encourages leafy growth rather than flowers.
• Allow room for the arching branches instead of repeatedly clipping the shrub to fit a narrow space.
• Remove unwanted rooted shoots at the base if the clump spreads beyond its allotted space.

Pruning. Prune immediately after flowering because next year's flowers form on older growth. Remove up to one-third of the oldest stems at ground level and shorten flowered shoots to strong younger growth; avoid winter shearing.

Early spring

Remove dead or winter-damaged wood, leaving healthy stems intact to preserve flower buds.

Spring

Refresh mulch and add compost if the soil is poor.

Late spring to early summer

Check tender shoots for aphids and wash off small colonies with water.

After flowering

Thin out old stems and reduce any branches obstructing paths.

Summer

Water young shrubs deeply during dry spells; take softwood cuttings from non-flowering shoots.

Autumn

Plant while soil is workable and moist, or remove unwanted rooted shoots from established clumps.

• Plant beside a terrace or frequently used path where the flower scent can be enjoyed, allowing space for arching stems.
• Use in an informal mixed hedge with other deciduous shrubs for seasonal flowers and screening.
• Place at a sunny woodland edge with ferns and shade-tolerant perennials beneath the outer branches.
• Combine with western North American native shrubs and perennials in a wildlife planting.

Garden styles it suits: Pacific Northwest woodland, Cottage garden, Woodland, Wildlife garden, Native hedgerow and Sensory garden.

Plant it with: Red-flowering currant, Oceanspray, Serviceberry, Oregon grape, Western sword fern and Yarrow.

Wildlife: Flowers provide pollen and nectar for bees and other visiting insects. The branching growth offers shelter and potential nesting sites for small birds.

• Aphids can cluster on young shoots; wash them off with a firm spray of water and encourage ladybirds and other predators.
• Powdery mildew may coat leaves in crowded or stressed plantings; improve airflow, maintain adequate root moisture and avoid excessive nitrogen.
• Poor flowering usually follows heavy shade or pruning at the wrong time; provide more light and prune only just after flowering.
• Persistently wet soil can cause root decline; improve drainage or move the shrub to a better-drained position.

Not known to be toxic to people, cats, dogs or horses. No part is recognized as poisonous, but it is an ornamental plant rather than a food plant, and eating plant material may cause digestive upset.

• Sweet mock orange (Philadelphus coronarius)

  Very similar in flower and habit. Its leaves are generally more consistently toothed along the margins, while western mock orange often has fewer teeth concentrated toward the tips;

• Mexican orange blossom (Choisya ternata)

  An evergreen shrub with leaves usually divided into three leaflets and white flowers usually bearing five petals. Western mock orange has simple deciduous leaves and four-petalled flowers.

The species name lewisii honours explorer Meriwether Lewis, while mock orange refers to the flowers' resemblance and scent to orange blossom.

Propagation. Take softwood cuttings in early summer or hardwood cuttings during dormancy. Layer low branches, or lift rooted basal shoots while dormant. Seed-grown plants vary and take longer to flower.

Accepted botanical name

Philadelphus lewisii

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alberta, British Columbia, California, Idaho, Montana, Oregon and Washington.

Measured

Soil pH 7 to 8. Average height 366 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.