Japanese maples are not fond of polluted skies but some acers can cope with emissions. Tilia’s (Limes) x euchlora are often used in urban areas since they are not only tolerant but actually absorb it too. Fragrant flowers in spring and providing beautiful autumnal colour.
Cotoneasters horizontalis (groundcover) / salicifolius (shrub) offer berries and necessary habitat in the winter months. An evergreeen that arguably could be thrown in a skip and survive. A very robust shrub. These are drought tolerant too.
Pyracantha coccinia (Firethorn) offers berries. Red and Orange. An effective shrub that can be used as a hedge. It has quite sharp thorns so equally a good deterrent. An evergreen providing foliage all year round. In spring, there are creamy white flowers. It’s hardy too.
Magnolia grandiflora, an evergreen will offer scented flowers in summer, Magnolia stellata and soulangeana have fragrant flowers too but these are decidious. Magnolia’s do prefer a partially sunny aspect and ideally a little sheltered. The latter flower in spring usually and without leaves.
Rhododendrons are low maintenance, providing flowers and some scented through spring into summer. The soil condition is of course important (acid) but dwarf varieties R. impeditum, R. ‘april rose’ can have fragrance and standard ‘Christmas cheer’ provide flowers, foliage and colour winter to spring. Rhododendrons are hardy but some evergreen and some decidious. For shrub varieties partial shade and for dwarf full sun.
Virburnums, ‘tinus’ the most common, are good at providing winter colour where there is none. A hardy shrub that can be used as a hedge. Be mindful, this is not a neat shrub. It needs to follow its natural habit and remain informal. It flowers through winter to spring providing fragrant flowers and attractive foliage. After this, it bears black berries. An easy shrub to look after, the aspect is not too important, the shrub is robust and withstands harsh conditions.
Sambucus nigra ‘Black lace’ or ‘Eva’ provide scented flowers and attractive foliage. It flowers in summer and bears fruit after. A member of the elder family, it is a tree but can be pruned to control its growth. A hardy shrub that prefers sun but generally tolerant of most conditions and most soils.
Escallonia is prolific in its growth. It can tolerate strong winds and resilient to most adverse conditions, but not the cold. Wind, yes but cold no. It is an evergreen but maybe choose a spot that is sheltered or coveted. It prefers more sun to shade and will provide you with pink flowers through the summer months. It has a tendency to become invasive to neighbouring plants so as a reminder, one it has flowered, give it a clip.