Mock orange (sometimes spelled as one word), generally speaking, is deciduous and multi-stemmed, with a height and spread that are roughly the same. It is classified as a shrub (bush), although you will occasionally hear people refer to mock orange "trees." Nectar-rich, mock orange shrubs are plants that attract butterflies.
In addition to the hybrids, a popular mock orange species to grow is Philadelphus coronarius, known commonly as "sweet mock orange" because of its pleasant fragrance. 'Aurea' is a compact (eight to 10 feet high) cultivar with golden leaves. 'Variegatus' is even more compact, reaching a maximum height of six feet; as its name suggests, it sports variegated foliage of white and green.
Characteristics of the Shrubs
'Minnesota Snowflake,' P. coronarius, and some of the other mock oranges exude a citrusy fragrance (the quality of which will vary according to species and cultivar). The plants bear light green leaves and produce white flowers in late spring or early summer. 'Minnesota Snowflake' reaches 8 feet tall x 8 feet wide at maturity. P. coronarius is listed as a somewhat larger plant (12 feet tall x 12 feet wide at maturity).
How to Grow Mock Orange Shrubs
Mock orange grows in USDA plant hardiness zones four through eight. Plant mock orange in full sun to part shade and a well-drained, loamy soil. The bushes generally blossom more profusely if planted in full sun. They are reasonably drought-tolerant shrubs once established.
Mock orange plants are at their most attractive in spring. Unhappily, they do not have much to offer during other times of the year; their ornamental value is not great enough for them to qualify as specimen plants. Massed along a border, they can form a loose privacy hedge for summer. The blossoms are often used as cut flowers.
Origin of the Name, "Mock Orange"
As the "mock" in its name suggests, mock orange is not a true orange. But the citrusy smell of its blossoms was enough to invite comparison, thus accounting for the origin of the shrub's common name. In the world of common plant names, "false" is the adjective typically used to indicate that one plant is similar in some way to another while being, nonetheless, botanically distinct from it. An example is false cypress.
Warning Before You Buy: a Questionable Smell
Fragrance is a major selling point for mock orange. Unfortunately, not all cultivars are equally fragrant. Consequently, a good time to buy mock orange is when it is in bloom at the nursery. Purchasing at this time assures you an opportunity to sample (based on aroma) before you buy. Reading plant descriptions is fine, but there is no substitute for sampling the fragrance for yourself, especially since our appreciation for smells is such a personal matter.
Care: Planting, Pruning Mock Orange Shrubs
For tips on planting mock orange in the ground after you get it home from the garden center, please see how to transplant trees and shrubs.
Your yearly pruning needs to take into account that mock orange blooms on the prior year's growth. Therefore, to avoid missing out on flowering next year, prune the shrubs immediately after the blooming period. On stems that have just finished flowering, prune off growth above where you see outer-facing buds. Also prune off any dead, badly-positioned or ill-formed branches, while you have the pruners or loppers handy.
As your mock orange matures, at some point you will probably decide that it is becoming mildly overgrown. It is time to apply the one-third rule, as you would when pruning lilacs. Each year, as you are doing your yearly pruning, prune the oldest one-third of the branches down to ground level. After three years of such pruning, the shrub should look healthier.
Even when mock orange becomes wildly overgrown, all is not lost, because the shrub, if healthy, will respond well to drastic rejuvenation pruning. Again, you will prune in the spring but, this time, before new growth begins. Prune all of the branches right down to the ground. You will not enjoy blossoms for that year, but all of the plant's energy will be channeled into the healthy new branches that will soon be rocketing out of your soil.