The 195 strong audience was made up of MSPs and representatives of gardening charities, community gardening groups as well as garden retail and nursery businesses from across the horticultural sector in Scotland.
The event, organised by the HTA and sponsored by Christine Grahame MSP, took place in the Garden Lobby at Holyrood.
Keynote speaker, Dr Aileen McLeod MSP, Minister for Environment, Climate Change and Land Reform spoke about the benefits brought by horticulture in Scotland which often go unnoticed.
She spoke about the vital role that the horticultural sector plays and how continuing collaboration is critical in getting issues such as plant health more widely communicated.
She publicly thanked HTA member and her own constituent Noel Allan from Galloway Heathers who provided MSPs with handmade heather buttonholes for the event, allowing them to demonstrate their support for Scottish horticulture.
Dr Richard Simpson MSP. patron of Thrive, said horticulture plays an important role in helping patients recover from mental illness and in dementia care.
HTA President Stan Green said: "Scotland has an amazing horticultural heritage – from internationally renowned parks, public and private gardens with many societies and community groups to boot.
"What better place to collectively celebrate the importance of plants in Scotland – than the Scottish Parliament. Horticulture plays such a pivotal role in society but do people, politicians and government take it seriously? More can be done."
Attendees were able to visit the parliamentary garden for the first time at a parliamentary evening reception, and were invited to put forward their ideas for how the garden might better reflect Scotland’s relationship and history with horticulture.