Callistemon, the Bottlebrush, is a hardy Australian native often found on drier stream banks where they can dip their "feet" into damp earth but keep their heads in the strong, hot sunshine. They thrive in the Auckland climate provided the soil dries out enough to allow the formation of a deeper root system.
These small, often semi-weeping trees covered in red, pink, or white bottlebrush-shaped blooms make attractive lawn or container specimens, look great in the back of a shrub or perennial border, and easily tolerate coastal extremes.
Several other shrubs look excellent when planted nearby. These include: Ceonothus, the California Lilac, a Western USA native which is covered with masses of tiny blue flowers in small, lilac-shaped clusters in spring. Foliage is small, glossy, and evergreen and the bush is easily maintained as a dense globe.
Cistus, the Rock Rose, is a slightly shorter, fairly compact but sometimes spreading shrub native to the Mediterranean. The thick textured leaves are masked in spring by large single flowers that closely resemble the wild rugosa rose in pink, white, and cream shades. These shrubs are coastal and frost hardy and will survive considerable drought.
Cytisus and Crotalarias are shrubby members of the pea family mostly Mediterranean and commonly called "Brooms". All have showy pea-like flowers often smothering the sometimes sparse foliage from late winter through spring and into summer. Colours range from the classic yellow and golden shades through red, peach and apricot to cream and white.
All are extremely drought and coastal hardy but the crotalarias are tender to extreme freezing and prefer some summer watering for best flowering. There are evergreen and deciduous varieties from 5 x 4m shrubs to creeping groundcovers under 1m. Best in poorer soils, sand, gravel and large containers.
Coprosma and Corokia are attractive NZ native shrubs most effectively in a dry shrubbery border. They are very hardy, drought resistant, effective in coastal plantings, and come in a variety of leaf colours and shapes. The NZ Cabbage Tree, or Cordyline, is also quite tolerant of drought as is the native tussock grass Carex and it's larger relative the Pampas or Cortaderia.
Caution! These are such strong growers that they may become invasive but are excellent especially on difficult, dry coastal margins. The Sheoke, or Casuarina tree will thrive in the same conditions as will Callistris, the Cypress Pine.
For colour try growing the sunny daisy coreopsis either as an annual or perennial along with the robust Canna lily. While noted for it's ability to live in swampland, Canna will flower in rich soils that dry out over summer. Hardy Campsis, the Chinese Trumpet Vine, will guarantee a spectacular display of orange trumpets all summer on a deciduous fast climbing vine. Under plant the lot with a beautiful evergreen groundcover, convolvulus mauritanicus, the creeping morning glory. While not invasive they create dense mats that hold banks, retain moisture as a living mulch, and reward with months of colour!