A consortium of Hillier, Oakover and Wyevale Nurseries has tendered for the contract, as has Crowders and Johnsons of Whixley individually.
Johnsons of Whixley director Andrew Richardson said he hoped showing flexibility in supplying HS1 would hold the North Yorkshire-based grower in good stead to supply HS2.
Richardson said he was confident the project would go ahead, despite a pause in planning post-Brexit/new Prime Minister/summer recess.
Richardson said: "There is a huge amount of open ground and field grown material in the contract. We quoted and will pull in stock from other suppliers in the UK."
He said HS2 may quote for trees separately.
AN HS2 spokesperson said: "This contract will be awarded to one company, and the anticipated award date is in quarter three of 2016."
Construction work on the first phase of the rail link is set to begin in 2017 and work is expected to be completed in 2033.
Growers say HS2 requires more than one million native trees and shrubs for phase one in 2017. Among the one million plants there are only 340 trees taller than the required 3m but 80,000 plants higher than 1m.