As the royal couple and baby Prince George prepare to leave Canberra for home on Friday afternoon after a wildly successful 20-day tour of New Zealand and Australia, the young family will have left behind some treasured memories and indelible images in the national capital.

A spectacular autumn day in the national capital served as the backdrop to one of those memories as six-year-old Canberra twins Oliver and Sebastian Lye helped Kate and William plant an English oak tree at the National Arboretum. Oliver put a brotherly arm around Sebastian – who has Down syndrome – as they watched Kate and William toss dirt on the tree.

After a busy day visiting Parliament House and the National Portrait Gallery, William and Kate attended a reception hosted by the governor-general Sir Peter Cosgrove at Government House.

The Government House reception for about 100 guests covered the spectrum from business to the arts to sport to charitable concerns. Also attending were Australia’s three serving Victoria Cross recipients Daniel Keighran, Benjamin Roberts-Smith and SAS Trooper Mark Donaldson.

At the reception, Kate wore a white cocktail dress by American designer Lela Rose after changing from her emerald green coat-dress by London-based design house Catherine Walker.

Earlier in the day Prince William spoke officially for the first time on this tour, telling a reception at Parliament House that he had told Kate that Australia would be wonderful and ‘‘so it has been’’. ‘‘Anticipation has become deep admiration,’’ he told the crowd of politicians and VIPs.

‘‘We go away with wonderful memories, and George goes away with his cuddly wombat, which he has taken to chewing so lovingly,’’ he said.

Prince William also praised Australia’s lifestyle and work ethic, acknowledging that it was known as the Lucky Country but ‘‘often the harder you work, the luckier you get’’.

‘‘Australians make their own luck,’’ he said.

‘‘The distinct Aussie formula that has fashioned such a dynamic society is the source of admiration and envy around the world.’’

Both Mr Abbott and Opposition Leader Bill Shorten made sporting references in addressing the royals, the prime minister reckoning ‘‘in Manly, you are bigger than [surfer] Kelly Slater, perhaps by a factor of ten’’ while Mr Shorten declared no matter who holds the Ashes ‘‘you and all of the members of your family will be embraced in Australia with affection and respect’’. Mr Abbott noted it was the 50th royal tour to Australia and ‘‘will be remembered as one of the very best’’.

Friday will see the euphoria replaced with solemnity as the couple attend the national Anzac Day ceremony at the Australian War Memorial as the country stops to acknowledge its war dead and wounded.

But Thursday will go down as another stellar day for Canberra, a city used to hosting world leaders and dignitaries . The city embraced the young royals with unbridled enthusiasm as fans thrust bouquets and presents for Prince George at the Duke and Duchess as they visited each location.

ACT Chief Minister Katy Gallagher, a committed republican who escorted the couple around the arboretum, happily conceded the royal tour had reignited interest in the monarchy,

‘‘I think the difference with the Duke and Duchess is that they’re really connecting with young people,’’ she said.

Ms Gallagher said it had been a privilege to meet the royals and their appeal was obvious.

‘‘They were very down-to-earth, very friendly and with a great rapport with everybody they met,’’ she said.

Ms Gallagher wore Australian label Anna Thomas while prime minister’s wife Margie Abbott wore a red design by Italian fashion house MaxMara.

Nine-month-old Prince George did not make any public appearances, kept safe and sound at Government House, but The Canberra Times reporter Jil Hogan got the scoop from Kate, the Duchess telling Hogan at the portrait gallery: ‘‘I’m sorry we couldn’t bring him with us. He’s very noisy’’.

Kate graciously accepted gifts for the young prince from school children at the arboretum, saying ‘‘his cot’s going to be full of little teddy bears’’. Other children gave the royal couple classic Australian children’s books such as Where is the Green Sheep? and Diary of a Wombat, which the young parents promised to read to George on Thursday night, their last night in Australia.

Annie Bourke, of Chapman, who spoke to the couple at the arboretum, echoed the thoughts of many when she said they had been very approachable.

‘‘They were so gorgeous, so beautiful. Very natural and lovely,’’ Mrs Bourke said.

Gemma Benn from Holt shook hands with Prince William outside the portrait gallery.

“And then Kate took the flowers from me and asked what they were and said they were gorgeous. I started tearing up,’’ she said.

The family is due to fly out of Fairbairn at about 2pm on Friday.