Reports said the grower was hit by poor weather and overseas competition. Receivers appointed to Highland Heathers have completed outstanding orders.
The family-owned company, whose main office is at Ford, near Lochgilphead, had a turnover of just over £2m. It supplied about two million plants to UK garden centres and landscapers.
A staff member at the company said: "I'm the last one here just tying up a few loose ends. Everyone else has gone." She confirmed the company went into receivership las week.
PKF corporate recovery partner Anne Buchanan said: "Although this is a long established company with a good reputation they have had a poor season in a difficult trading environment with increased competition from overseas.
"The company has been profitable to date but a poor sales season due to the wet weather coupled with high overheads has resulted in the business making a loss.
"Unfortunately we do not believe it can be sold on and we will complete some outstanding orders before letting the staff go and closing the business in the next few weeks."
Highland Heathers was a supplier to Focus but was listed as a creditor to the tune of £43,000 after the retailer went into administration in 2010.