Learn Philadelphus Lewisii Care [Mock Orange]

Philadelphus Lewisii [Fil-uh-DEL-fuss, Lew-ISS-ee-eye] is a deciduous shrub from the family Hydrangeaceae (Hydrangea). 

This plant is native to North America, east to Montana and Idaho, north to southern British Columbia, and northwest California.

Flowering mock orange (Philadelphus lewisii)

The Philadelphus Lewisii var Gordonianus is widespread, yet uncommon as it typically appears as an individual plant among other plant species. 

This plant is named after Meriwether Lewis (explorer and scientist), who was the first to collect it during Lewis and Clark expedition in 1806.  

The common names of this plant include:

  • Mock Orange
  • Lewis’ Mock Orange
  • Syringa
  • Wild Mock Orange
  • Indian Arrowwood
  • Gordon’s Mock Orange

Mock Orange Philadelphus Lewisii Plant Care

Size & Growth

Philadelphus lewisii is a multi-stemmed shrub that grows around 4’ to 6’ feet tall and has arching branches. 

It produces oval green leaves, which turn yellow during the fall season. 

Its bark is reddish-brown and gradually turns gray as it ages.

These “orange blossoms” like plants grow in different habitats, including sagebrush deserts, rocky slopes and hillsides, forest edges, moist open woodlands, and streamsides.

Flowering and Fragrance

The lewisii philadelphus aka Indian Arrowwood produces clusters of three to fifteen white flowers, with yellow centers and four petals. 

The bloom time of this plant is May to July. 

The flowers have a sweet scent, which some people compare to orange blossoms, others compare it to jasmine, and some believe it has a hint of pineapple.

Once the petals fall, you will notice the sepal they leave behind. 

These sepals look like flowers and offer a prolonged seasonal interest.  

This plant is the state flower of Idaho.

Light & Temperature

The Mock Orange plant thrives well in full sun but also performs well in part shade. 

The shrub will blossom more copiously if you place it under direct sunlight. 

Be sure to provide it partial shade from the harsh afternoon sun.

The recommended USDA hardiness zone is 4 to 8. 

This plant is winter hardy and doesn’t require any protection during the winter season.

Watering and Feeding                                                           

This native plant of the Hydrangea family is drought tolerant and will survive merely on rainfall. 

However, it might need additional water to flower more and thrive better. 

Provide it with 1” inch of water every week. 

Increase the amount during dry, hot weather. 

Decrease the amount during the colder months.

This shrub is not a heavy feeder but will benefit from a water-soluble fertilizer in late spring if it isn’t growing well. 

Never use a nitrogen-rich fertilizer as it will drastically enhance leaf growth and decrease or even stop the growth of blossoms.

Soil & Transplanting

The Lewis’ Mock Orange doesn’t have specific soil requirements.

It grows well in heavy, medium, and light soils. 

The plant even tolerates heavy clay and poor soils.  

Grooming and Maintenance

This plant requires regular pruning to keep it dense and to prevent it from overgrowing. 

Utilize the one-third rule of pruning lilacs here. 

Annually, prune one-third of the plant’s oldest branches down to the ground level. 

It will gradually start looking healthier.

Make sure the plant grows in moist conditions for healthy growth and blossoms. 

You may mulch the surrounding of the shrub assist the soil in retaining more moisture, and for reducing the watering needs.

How to Propagate Mock Orange

Propagate this plant with a cold stratification method. 

  • Sow the seeds in a cold frame and place it in a well-lit position. 
  • Once it is big enough, prick out the seedlings and plant them in individual pots. 
  • They should be kept in a greenhouse for the first winter. 
  • Place the growing plants in their permanent positions during early summer.
  • Cuttings are also used to propagate this plant. 
  • Take 2” to 4” inches of shoots and grow in a shaded frame. 
  • Transplant them in their permanent position during the spring season.

Mock Orange Plant Pest or Diseases

This plant doesn’t experience severe pest or disease issues. 

However, be on a lookout for aphids. 

Wash the pests off from the leaves. 

Use a homemade insecticidal soap if the aphid population continues to grow.

Usually, problems arise due to water issues — overwatering results in root rot and underwatering results in stunted growth and inadequate blossoms. 

Keep a check on the moisture level of the soil. 

If the soil is about 2” inches dry, water the plant. 

If you notice the leaves curling or wilting, water the plant.

The plant might also get infected by powdery mildew if it isn’t growing in ideal conditions. 

Spray it with sulfur or copper fungicides to prevent the spread and prune off the affected branches.  

Philadelphus Lewisii Plant Uses

The deciduous shrub Mock Orange makes a stunning addition in any garden due to its fragrance

The arching, tall branches, and flower color make it an ideal backdrop for other plants. 

It creates a sense of stature and structure in the garden.

The leaves and flowers of this plant are loaded with saponins. 

Therefore, they are used as soap bars since they create a frothy lather when mixed with water. 

This plant is deer resistant but attracts various pollinators, including hummingbirds and bees.

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