Philadelphus is a group of elegant, hardy shrubs producing masses of single or double, cup-shaped white flowers, sometimes blotched maroon or pink in the centre, from May to July. Commonly known as Mock Orange given its delicious, strong, citrus-like scent, it forms an attractive framework of arching branches and light green or golden deciduous foliage. Philadelphus commonly grow to around 1.8 metres (6 feet) but there are both dwarf and much taller varieties available as well. Sometimes confused with Syringa, they make a beautiful backdrop to roses and herbaceous perennials and work well in the mixed border or a large container situated close to a seating area or doorway. Mock Orange will grow almost anywhere – in poor soil, industrial smoke or salt-laden air – the only conditions that cause them problems are boggy soils that lie wet. That said, for the best display, give them a sunny spot and learn how to prune them properly. Prune after flowering in late July or August, cutting one-quarter of old growth back to a good bud, or down to ground level if this helps eliminate over-crowding. This will help promote new growth and encourage more abundant flowering.