When you visit another country you often have a preconceived idea of the colours in the natural environment you will encounter. This is particularly the case today with instant news and documentaries on television. However during the first years of the colony the convicts and their guards would have been amazed at the different style, variety and colour of the vegetation they encountered.
The bush near the coast would have been scraggly with trees they had never seen before. So many different varieties of eucalypts - some with long narrow leaves, others round - and not the bright or dark green of English foliage. The variety of bark to be found on the trees plus the different types of colours of flowers and shapes of seed pods would have also been a new experience. They would also encounter multiple varieties of wattle with their mass of yellow flowers in late winter and early spring along with the large flowers of the red waratahs and the banksias with their yellow or orange flowers before revealing dramatic seedheads. Instead of green fields there was grass which died off or turned yellow during the hot summer.
Arriving in summer there would have been days of blue sky and sunshine accompanied with a sub-tropical storm from time to time. The first settlement was on the coast so they would also experience the changing moods of the sea. For those who had come from towns and cities this would be a new experience, once they had recovered from their long sea voyage.
As time went on and the settlers began to explore inland they would encounter large areas of saltbush and further inland the desert. I love the rich colour of the desert, especially contrasted against a bright blue sky but this would have been a shock to many hoping to settle and farm this land. Those who explored north on the east coast would encounter the rain forests - another environment again.
Colour of the landscape would have been just one of the sensory challenges. There would also be different different smells / scents of the vegetation, not to mention the strange widlife encountered.
Over time the Europeans brought many of the trees and plants from their countries to grow in Australia and we now have a mixture of vegetation and colour in our gardens. The initial impact of a new palette of colour created by vegetation and climate would have had an impact on the first European settlers in Australia.