Phenology

As I marvelled at the flowers of the reed-leaved bird-of-paradise (Strelitzia juncea) glowing in the winter sun yesterday at one of our Auckland projects, I reflected upon the value of regular observation of events within gardens and landscapes. Over the last 2 years, we have started to record such events on a phenology database, so that we can build up a comprehensive picture of just what is happening throughout the seasons.

Phenology is the study of events within the natural world; when they occur, what form they take, and how they are affected by external influences. From the point of view of a landscape designer, it is a basic requirement for being able to compose diverse plantings that provide a shifting cast of ‘actors’ (such as the glorious, winter-flowering Corylopsis pauciflora, pictured below) throughout the year.

It is a form of observation that is not valued enough within contemporary landscape architecture within New Zealand, with the exception of some records of flowering times for a limited range of native revegetation species – which are readily accessible via Council documents and revegetation guides. Compared with such minimal observations of phenology, the knowledge of seasons applied by Piet Oudolf in his dynamic schemes looks positively mystical.

The springtime appearance of either bulbs (such as Ferraria crispa, shown above, or freesias) or native trees and shrubs (such as kōwhai or kumarahou) become events against which our lives are, to some degree, calibrated. The relationship between the late winter-flowering Clematis paniculata with puahou (Pseudopanax arboreus), Rehua (and the stars associated with it) and tuna (eels) within whakapapa traditions shows the manner in which certain events guide the lives of people. In this case, these plants and celestial bodies act as signals towards the running of tuna (eels), which Māori would then harvest.

The life cycles of bulbs are timed to all seasons, and some of the most spectacular specimens erupt forth in autumn. My friend and mentor, Terry Hatch, was particularly pleased to receive some return on his efforts with the South African species shown above (Brunsvigia josephinae), which he and Lindsey have grown for decades (probably more than half of Lindsey’s life) prior to their first flowers appearing this year.

The commonly grown white amaryllid pictured above has an interesting origin, which appears to be commonly misconstrued. Derived from intergeneric crosses between Brunsvigia and Amaryllis, this white form (with a yellow throat) is commonly known by the name ‘Hathor’, after an early Australian garden where breeding between these bulbs was carried out.

However, there are similar varieties that do not conform to ‘Hathor’, and it is therefore difficult to say definitively what it should be called. In the end, the main thing that matters to us is that this long-lived bulb reliably sends up its spectacular white blooms at a time of year (late summer) when the majority of flowering bulbs wouldn’t countenance such a rash act.

Much like Brunsvigia josephinae and its progeny, the blood lily (Haemanthus coccineus, pictured above) ensures maximum effect (with natural pollinators and gardeners) by sending its flowerheads up (in autumn) unaccompanied by foliage. The beautiful Haemanthus shown below in a suitably expansive clump is probably (if memory serves me correctly) the ‘love child’ between H. coccineus and the evergreen H. albiflos, a combination that (like many other hybrids) throws out a wide variety of forms.

Following the autumnal displays of these Haemanthus (or the appearance of autumnal leaf colour in colder climes), flowers from Lachenalia or Narcissus brighten winter’s often sombre atmosphere. Through focussing one’s attention on phenology, the possibilities for landscape architecture expand exponentially; especially with respect to the performance of plants within one’s own climate.