Two people were killed and 298 suffered major injuries in gardening and grounds upkeep, while one person died and 15 were seriously injured across horticultural trades this year, latest figures from the Health & Safety Executive showed.
Nine were seriously injured in propagation, 33 in retail and 165 in landscaping.
Agriculture, forestry - including tree surgery - and fishing saw 34 deaths among more than 1,000 injuries. But the findings confirmed Britain had Europe's lowest rate of fatal occupational injuries, said the HSE.
Lantra horticulture, landscaping and sportsturf industry group chair Neil Huck said: "The figures represent quite a low percentage of accidents. I'd like a finer breakdown of the categories and kind of accidents, especially those rated 'serious'."
He said: "Lantra is reviewing national occupational standards and I would like to see a stand-alone health-and-safety qualification - it's currently a unit within a qualification. We need to know if riders know what a 20 degs angle looks like."
Institution of Occupational Safety & Health rural industries group chair Graham Munford said: "We are concerned that the rise in workplace fatalities is a knock-on effect of belt-tightening."
NFU head of policy services Andrew Clark said: "There is a tragic story behind each number. But the launch of the Farm Safety Charter last May is one positive step."
HTA training and careers manager Penny Evans, said: "Both employer and employee have responsibilities. Health-and-safety practice should be so integral that they are the norm rather than being viewed as a tick-box exercise."
HSE chairwoman Judith Hackitt insisted the drop in injuries reflected an "ongoing trend" but she raised concern at the hike in fatalities, warning against ever "letting up in our commitment" to tackling serious risks.
"We will continue to work with employers, employees and other organisations to maintain and, where necessary improve, health and safety standards. We all have a responsibility to make sure that serious workplace risks are sensibly managed."
Industry injuries and deaths - In statistics
Some 171 workers across all sectors were killed, up from 147 last year, and there were almost 25,000 serious injuries last year.
Injury and ill-health is estimated to have led to 26.5m working days being lost across the industry - 22.1m to ill-health and 4.4m to injury.
In the agricultural sector there were 221.9 major injuries per 100,000 employees - one of the highest levels of work-related injuries reported.