On receiving the seeds earlier this month, they fretted over their poor quality. But encouraged by the successful germination of a few seeds in a saucer on my kitchen windowsill in Washington, DC, they went ahead with planting.

In an email yesterday, Nicola Hinder, assistant secretary for Biosecurity Pathways with the Department of Agriculture, said: "I am pleased to let you know that there is cautious optimism from our end. We still have a way to go – [but] from the large number of seeds sown, we have achieved a small germination rate.

"At this point, and noting that more may pop up in the next few days, we have about 20 plants in their very early stages and I understand that we should start to see some dramatic growth in the next few weeks."

It will take about 20 or so weeks for the seedlings to mature and start to produce seeds. Saying that each sunflower head typically produces about 1000 seeds, Ms Hinder estimated that if all the plants matured, they might produce about 20,000 seeds – "I think that this will meet your requirements, as it should work out to be a larger number than you brought back."

But she cautioned: "This is of course an upper estimate – they will need to mature before I can put a reliable figure on the amount of seed we may see towards the end."

On maturation of the plants, she explained: "We will need to dry the seeds off and provide them back to you.  Our plant pathologists will continue to monitor them for signs of disease, and should any symptoms be observed the  plants will be tested to determine what is present and the options available."

Photographer Kate Geraghty and I harvested the seeds by hand in the field where the cockpit section of the Malaysia  Airlines aircraft crashed after being struck by a missile fired in the separatist war raging in Ukraine last year – killing 297 passengers and crew, including 38 from Australia.

Stepping carefully between the demands of Australia's rigid quarantine regime and a need to respond sensitively to provide victims' families and friends with lasting, self- regenerating mementos sourced from the crash site, the department has gone to extraordinary lengths to make the seed venture a success – having the seeds couriered to Australia and waiving all fees and offering to have some of the seeds set in resin as an alternative for family and friends unable or not inclined to grow the seeds.

Ms Hinder said: "I really do want to pass on my thanks for your willingness to work with us to manage the biosecurity risk these sunflowers could pose to our environment and agriculture production.

"It is my belief that we can manage the importation risks and help you provide those families and friends of the MH17 tragedy with a fitting living remembrance."