Survival of the fittest: putting Australia’s plants to the test

The Royal Botanic Garden Sydney’s horticultural team are putting plants to the test in a range of experiments, to see how well different varieties survive in Sydney’s ever-changing conditions.When you think of the word experiment, most people would picture a person in a white lab coat, goggles, with a variety of chemical concoctions, locked into a windowless and sterile lab.

My team on the other hand are equipped with gardening gloves and hats, on top of the Sydney Conservatorium of Music surrounded by flowerbeds and fresh air. Personally, I think we have the better deal. This area is what we call our new ‘Trial Garden’. The aim of our experiments is to investigate how well different selections of plants grow in the changing Sydney conditions. Our role at the Garden is to not just conserve and research, but also to act as a source of garden information. We are the people you can come to for advice on what to grow on your balcony or in your garden, which will last all season and make your neighbours jealous.

What we are testing

The growth of a plant is influenced by many factors; soil, temperature, water, exposure and disease are just some of the elements that come into play. Different plants will prefer and thrive in different conditions, just as different areas of Sydney and New South Wales, will have different soil, water and levels of exposure.

We are testing all different types of plants to see how these conditions influence their growth, right down to whether or not cockatoos like them or not. This way, we can find the toughest and most resilient plants for every condition.

In the last year over 230 varieties of plants have been tested in our Trial Garden. The current top 5 performers are:

1. Euphorbia hypericifolia 'Stardust' – This one has been blooming in the Trial Garden for 9 months straight, with no pest or disease issues at all. It doesn’t need pruning to maintain shape and grows well in wet or dry weather.

2. Salvia x hybrida ‘Mystic Spires Blue’ - This hybrid perennial Salvia has been a blooming machine for almost 12 months. Bright blue spikes of flowers through the heat of the summer and cooler weather. A beacon to every butterfly and bee in the Trial Garden.

3. Pelargonium x hybrida (Geranium) ‘Big Pink’ -  No rust, constant flower and no need to prune this beast of a Pelargonium. Hot pink flowers have been produced constantly since planting over 11 months ago. No signs of rust that Geraniums often get in Sydney’s humid summer.

4. Impatiens x hybrida ‘Sunpatiens Compact White’ -  Perennial Impatiens that stay compact and handle full sun and heat of Sydney. The plants are constantly coated in white flowers which stand out from the coloured plants.

5. Lobularia x hybrida ‘Snow Princess’ – This isn’t your grandmother’s sweet alyssum. These plants have flowered non-stop for 12 months in Trial Garden and each plant has spread to a metre across. If the snow like effect of the flowers doesn’t get your attention the amazing fragrance will.

Why it is important

Being able to advise the public on the which plant will survive the best for them isn’t just about which one we find to be the most attractive.  We’re testing to find those that don’t just look good for a few weeks but for several months and require less water, fertiliser and labour to maintain.

What to know more?

We are testing plants supplied by plant breeders from Australia and around the world. At any time you will see a selection of annuals, perennials, grasses, turf varieties and shrubs added to the testing grounds to see how they perform. We recommend you come by the Trial Garden and pick your own personal favourites.  In the future we have plans to install a plant trail program at the Australian Botanic Garden Mount Annan, which will be dedicated to testing only native plant species and their suitability for home gardens.

Stay tuned for the preliminary results from the test in June 2018 and follow me on Twitter (@TexaninOz) for updates about our work.