A passion for native plants

Sunday, 12 August 2012

A view of part of the garden created by Brian and Carol Roach

I am woefully ignorant about Australian native plants. I enjoy seeing them growing wild when I am going on a bushwalk but I have no idea about how to incorporate them successfully into a home garden. So it was a great experience for me this week to visit the garden of Brian and Carol Roach in north-west Sydney, and see a stunning garden of flourishing native plants. This garden was established more than 30 years ago - after the removal of the previous owners' many Camellia and azalea plants! Winding paths were formed by excavating soil and mounding it up on either side, thus creating raised beds that do assist in providing the good drainage that some native plants like. The clearly defined beds give an excellent structure in which to position the plants and allow visitors to get right up close to the many exciting specimens on display. Several tall trees in the garden (including a superb gnarled Banksia serrata) provide height and a sense of shelter. There is a bush reserve directly behind the garden with towering gum trees, many with wonderful white trunks, providing the perfect backdrop for this exceptional garden.

Chorizema cordatum in the garden of Brian and Carol Roach

Brian has a wealth of experience in growing native plants and has more than 400 different species of them in the garden today. Through his experimentation, as well as the exchanging of plants with other keen native plant enthusiasts, his garden offers many lessons in what grows well in our climate. Many of the problems that gardeners in years gone by had in growing Australian natives stemmed from the fact that there are so many different climates in Australia, so what grows well in West Australia, for example, is not necessarily going to do well in humid Sydney, even though it is a 'native plant'! However, some do, and growing right at the front of Brian's garden is one of his favourite plants, Chorizema cordatum (ht 1 m), the West Australian Flame Pea. This is a fabulous-looking plant, with large pea flowers in brilliant colours of orange, pink and yellow in late winter and early spring. It grows very well in Sydney and is apparently best in a dappled light or shaded position with reasonable drainage. Several of my friends and I could not resist buying one of these from Brian's nursery at the end of our garden tour, and I am so looking forward to adding mine to my shaded hot-coloured border.

Grevillea Peaches and Cream in the garden of Brian and Carol Roach

Many West Australian plants that don't thrive naturally in our climate will perform well if grafted, and we saw a number of these during our visit, including Grevillea specimens grafted onto silky oak (Grevillea robusta) rootstock. Brian has a wide variety of Grevillea plants growing, with a diversity of flower sizes and foliage textures: leaves ranged from very thin, pendulous forms like a pine tree (such as Grevillea petrophiloides, with large, pinkish-red brush-like blooms) to one that resembled a holly bush (Grevillea flexuosa)! Lovely dainty-flowered Grevillea contrasted with some of the big, flamboyant 'tropical' types, such as 'Peaches and Cream'. Note that some people are very allergic to these latter types, so caution needs to be exercised if you plan to introduce them into your garden. Brian told us that he cuts many of his Grevillea back very hard each year to keep them compact. Many are pruned after flowering but the tropical forms are done in the warmer months between November and March. Pruning is vital for many native plants to preserve a good shape.

Brian's keen eye for exceptional forms of native plants has led to a number of varieties being introduced to the nursery trade. For example, a compact form of the NSW Christmas bush (Ceratopetalum gummiferum) with brilliant red calyces and growing to just a little over 1 m in height, was a form that had originally evolved on a harsh headland in the Ballina region. He has since propagated it successfully and given it the name of 'Johanna's Christmas' - it will be released commercially in the near future.

Large-flowered form of Geraldton wax, named Whopper Wax, in the garden of Brian and Carol Roach

Other good forms of plants that he has spotted include a gorgeous large-flowered form of a pink Geraldton wax (Chamelaucium), which he has named 'Whopper Wax', and a beautifully perfumed Grevillea that he has named 'Honey Jo'. There are many fragrant plants in the garden and we enjoyed fondling Prostanthera leaves, and smelling a number of flowering Boronia plants, including the Sydney Boronia (B. ledifolia). Brian told us that Boronia can be grown very successfully in pots, as this gives more control over their need for moisture. He also grows a number of other natives in pots through the garden.

Mingled groundcovers Zieria prostrata and Brachycombe in the garden of Brian and Carol Roach

The plants are arranged with an excellent sense of contrasting size, foliage and form, to avoid the effect that can sometimes occur when many native plants with small, thin leaves are planted together, forming something of a amorphous blur. Bold-leaved plants such as the dramatic sculptural Gymea lily (Doryanthes excelsa), which were just opening their amazing red flowers, form a counterpoint to the fine-leaved plants. The use of lots of strappy-leaved foliage plants - such as kangaroo paws (Anigozanthos cultivars ), Lomandra and Libertia also provides contrast, as does the recurrence of grey-foliage plants through the garden - including some very healthy-looking flannel flowers (Actinotus helianthi) that will be blooming soon! Brian told us the key to success with flannel flowers is to feed them well twice a year. Groundcovers such as glossy-leaved Zieria prostrata, Scaevola and various Brachycombe, with their dainty daisy blooms, appear beneath many of the plantings and help knit the garden together into a cohesive whole.

Native greenhood orchids, Pterostylis curta, in the garden of Brian and Carol Roach

Native orchids - both epiphytic and terrestrial - feature in the garden, providing another contrast of flower and leaf form. We were particularly fascinated with a patch of tiny, dainty 'greenhood' orchids (Pterostylis curta) growing beside a path. These had apparently been dormant for 30 years but re-emerged when the path was dug up a few years ago. They flower in late winter and early spring and die down in summer. They can multiply quite rapidly over time.