Parks champion Alan Barber was appointed OBE, while National Society of Allotment & Leisure Gardeners (NSALG) chairman Allan Rees was appointed MBE.
Former Bristol City Council head of parks Barber received the accolade for services to the environment. "I am thrilled to receive the award," said Barber, who was a CABE commissioner from the inception of CABE Space in 2003, until he stepped down last spring due to ill health.
He added: "I would like to thank all those who have supported the call for greater care to be taken of our parks, including Horticulture Week and all those nurses who have kept me alive to see the day."
Last year, Bristol City Council honoured Barber for his contribution to parks in the area with the opening of a rose garden named after him.
Barber said: "To try to dispel rumours that the OBE has been awarded posthumously, I have a 5,000-word paper going into the Journal of Chinese Society of Landscape Architecture next month, written with Junfang Xie."
CABE Space director Sarah Gaventa said: "It is overdue and well-deserved and, at last, Alan has got official recognition.
"It demonstrates the Government's recognition of the importance of work in this field."
On HW's website, parks colleagues were quick to praise Barber for his accolade.
The Parks Agency director Stewart Harding said he was delighted Barber had been recognised. "(It is) a well-deserved recognition for his devotion to the cause," he said.
Oldham council parks manager Steve Smith added: "Everyone who knows Alan or has listened to his speeches at conferences will know that no one is as passionate about our beloved parks and countryside as he is, or has done as much to raise the profile of the sector."
The award is a coup for the parks sector as it is an area infrequently recognised in the honours list. Most recently, Barbara Wilson was awarded the MBE in the 2005 list for her work for the Friends of Coalshaw Green Park, in Oldham.
The year before, Friends of the Sheffield Botanical Gardens chairman Dr Sue Kohler was also appointed MBE.
Rees said: "It is not ever really about one person; it's the whole gardening fraternity."
He added: "It means a lot to the gardening world to get something like this and is recognition of the work of all the people gardening throughout the country."
Rees said funding from local authorities for allotments remained a problem as demand increased, but he hoped the award would raise the profile of horticulture. "When people see the gardening world has been recognised, perhaps local authorities will sit up and do more to provide allotments."