Gardens: Understanding microclimates MY COAST

Gay Hannigan’s lakeside garden. Use interesting foliage to enhance a tropical garden. These beefsteak plants and croton thrive in dappled sunlight.

UNDERSTANDING MICROCLIMATES

WORDS PAUL URQUHART PHOTOS LISA HAYMES

OVER THE YEARS, WE’VE BROUGHT YOU MANY EXAMPLES OF GARDENS IN COAST MAGAZINE. THE ONE THING THAT MARKS THEM IS THEIR DIFFERENCES: FROM RIVERSIDE GARDENS TO COASTAL FOREST, FROM TROPICAL STYLES TO JAPANESE, AND FROM AVERAGE SUBURBAN GARDENS TO LARGE COUNTRY PROPERTIES. DESPITE THEIR DIFFERENCES, THE ONE THING THAT UNITES THEM IS HOW THEY TAKE ADVANTAGE OF MICROCLIMATES.

We hear a lot about climate and climate change – not so much about microclimates. Here on the Central Coast, the terrain and temperatures vary greatly from the coast to the hinterland and from the hilly, forested south to the drier plains in the north. Gardeners need to know the differences so they can get the best results in their own patch.

With lockdowns and working from home, many of us have spent more time in the garden and bought more plants than ever before, but how many of these expensive purchases have survived or better still thrived? If we understand our own local microclimate and even how we can create a microclimate, then success will come more readily.

SO, WHAT IS A MICROCLIMATE?

Simply, it is a small area within a climate zone that exhibits different conditions to the dominant zone. If, for instance, you drive from Wyong to Doyalson and Lake Munmorah, at one end you’ll see stunted eucalypt forests together with melaleuca thickets that indicate low fertility in the soil and a tendency to swampiness. Further on, forests of taller angophora are dominant. These are trees that thrive on low fertility and like soils that are sandier and free draining. So the differences in the soil profile, the lay of the land, (whether flat or hilly), proximity to watercourses or lakes, and exposure to wind and wind direction can all affect the microclimate.

In the south, say around Avoca, Empire Bay or Pearl Beach, there are gullies, hills and a proximity to the coast that creates richer valley soils and streams and, as a result, the natural tree cover is taller, lusher and wetter.

Further west, other variations occur. Yarramalong and Dooralong Valleys with silty or clay soil, can be frosty in winter and definitely colder overnight. Valleys, in general, also tend to be hotter in summer than coastal locations tempered by sea breezes. These are the go-to places for a quick fix of autumn foliage. Head 300 metres up to Peats Ridge or Kulnura, and sandy soils – generally known as Hawkesbury Sandstone – coupled with exposure to southerly winds, mean that the climate regulates what will grow successfully. YOUR OWN MICROCLIMATE

The mere act of planting a garden can be the start of creating a microclimate.

Trees create shade and can lower summer temperatures and conserve moisture. Expansive lawns without trees or shrubs allow houses in the same position to heat up, so the microclimate would be drier and hotter. What you plant is also dependent on your local soil and you wouldn’t necessarily choose to grow arid zone plants like cactus and other succulents or inland natives in a shady garden with clay soil.

Leonie Grimshaw’s coastal garden. Make the most of local trees such as angophora, which thrive in poor sandy soil by the coast.

Bill Burton’s riverside garden. Near rivers, where the water table is high, cabbage tree palms thrive.

Living Edge hinterland garden. Native eucalypts offer shade and protection for more tender plants.

OUR COASTAL GARDENS

Gay Hannigan’s garden (COAST magazine, Autumn 2019) at Long Jetty is a tropical oasis with palms, heliconias, ferns and frangipanis. THE METHOD: 1 Take full advantage of your position. Gay’s garden is adjacent to a coastal lagoon with its cooling, moist atmosphere. This keeps it cool in summer and warm in winter. 2 Plant exuberantly. Gay accentuated the area’s natural microclimate by planting a protective cover of palms and native trees. This created a cushion of warm air where warmth-loving tropical plants thrived. They are protected from scorching sun in summer and cold in winter.

Bill Burton’s riverside garden on the Wyong River (COAST magazine, Autumn 2021) has to contend with regular flooding and anaerobic soil common to swampy ground. (Anaerobic soils have a restricted flow of air within the soil pores, because of their high moisture or water table level – sound familiar after our high rainfall season?) THE METHOD: 1 Work with what you’ve got. Tall coastal trees help soak up water when it comes and you can choose complementary trees to add interest. Bill planted palms suited to similar conditions. They also direct your eye to the ground plane where Bill planted ferns and a mix of natives and exotics that thrive in damp soil. 2 Build up the soil. Compost and mulch alleviates some of the effects of oxygendepleted soil and as the soil profile gets higher, plants are less likely to drown. Leonie Grimshaw’s Bateau Bay contemporary garden designed by James Headland of Pangkarra Gardens is close to the beach where the beautiful red gums (angophora) make such a statement. (COAST magazine, Autumn 2020). THE METHOD: 1 Use the location. The garden takes its cue from its coastal location and uses a largely native planting of grasses, shrubs and groundcovers. Most of the indigenous trees were preserved and beds created around them. 2 Make it practical. Gravel paths allow water to drain away naturally and a small but perfectly formed productive garden is close to the barbecue and deck. Because the climate is warm here, a few tropical plants give extra lushness.

Living Edge Nursery and Garden (COAST magazine, Spring 2019) is located on a rural property at Peats Ridge, has sandy free-draining soil, which posed some problems in creating a microclimate. THE METHOD: 1 Improve the soil. Owners David Fripp and Blake Jolley added tonnes of rough mulch applied to a depth of at least 30 cm. As it broke down it became a fertile bed for many different plants to thrive. This process continues. It’s not a one-off. 2 Mix and match plants. Surrounded by bushland, the garden blends seamlessly with common plants used in uncommon ways. At the same time, experimentation allows more uncommon species to fit in and thrive.

Gay Hanigan’s lakeside garden. A lakeside location is generally warmer and more humid, ideal conditions for tropical plants. Living Edge hinterland garden. Copper spoons backed by Gymea lily demonstrate synergy between indigenous and exotic plants.