How to grow Philadelphus the Mock Orange shrub

Philadelphus is an easy to grow deciduous shrub, which flowers in late spring and early summer. Philadelphus has attractive pure white flowers and a wonderful scent which is why it is known as The Mock Orange Shrub. In terms of growth, different varieties grow between 1.2m and 3m. There are several popular garden varieties  which are fully hardy to H6, which is -15, which makes it tolerant of UK winters. 

 Philadelphus will benefit from pruning, although it is not essential every year.

You can tell if it needs a prune if either the shrub is getting too large; it has developed some spindly branches;  or it is flowering less. Pruning will promote more growth and vigour. The best time to prune Philadelphus is after flowering, which will be late in July. Cut back to good bud and /or remove about a quarter of the old growth. In common with many shrubs, regular pruning removing some of the older growth will promote new growth, and better flowering. If pruning regularly every year, it is common to remove one third or a quarter of the old growth down to the ground.  

Over time, Philadelphus can become woody, with all the flowers at the top, and long wood/cane like stems which look unattractive. Philadelphus belongs to that group of shrubs which will tolerate hard pruning and come back although it may take more than one season. If your Philadelphus shrub has become overgrown and unsightly, prune it hard, around July, after flowering down to 1ft/ 30 cms.The Mock Orange flowers on the previous year's growth, known as “flowering on old wood”. If you prune hard to renovate, it may not flower the following year but should put on a good deal of growth and by year 2 will look a great deal better and blooming.  

Philadelphus can be grown in a container. It is a shrub which major highlight is the scented flowers and some gardeners feel it looks a bit drab post flowering. It would make an ideal patio shrub where the wonderful scent could be enjoyed and moved post flowering to fill a border gap with greenery.   

Like all container grown plant it needs to be well watered to get established. To grow in a container pick a suitably compact variety such as P."little white love" which is scented and reaches around 1m,  available from Thompson and Morgan read more about it  or P. Manteau d'Hermine' compact with very fragrant flowers which reaches around 1.5m. ( available from Crocus affiliate link here)

Popular, easy to grow varieties, include:

1. P.'Belle Etoile' illustrated above right,  a more compact variety up to 2m, fully hardy arching branches with many very fragrant flowers. A single flowering variety which is attractive to bees. Available from Crocus 
2. P cornonarius is the varitey most commonly known as the mock orange shrub as it possibly has the most strongly scented flowers. White blooms with yellow centres (illustrated above centre) the flowers are around 2.5cms wide. Once established the shrub is drough resitstant and it will tolerate all soil types and partial shade. Height around 1.25m.
3. P. coronarius

   Aureus

   starts with bright yellow foliage in the spring which fades to a chatrese green later in the year. The flowers are scented with a touch of lemon. It is will reach around 1.5 m. 
4. P. 'Boule d'Argent'  is less fragrant, but has the advantage of semi-double to double white flowers.
5. There is a golden yellow leaved variety P.'Aureus' which grows up to 2.5m.
6. P. Mexican Jewel' has white flowers with purple centres. It is scented and said to smell of bubblegum.

The shortness of this text is a testament to how easy it is to grow Philadelphus,  and so rewarding, with a  profusion of blooms and scent.

Updated 18.12.2023