Shropshire Council would not determine the application because of a holding objection from Highways England over the complex on land at Weston Road, next to Oswestry's bypass.
But this week Government inspector Robert Parker granted permission.
Local company Knotwood, from Coed y Go, says that up to 70 jobs could be created at the new garden centre.
Mr Parker said that the main issue in the case was the effect of the proposed development on highway safety on the strategic road network, particularly the junction of the A483 trunk road with Maesbury Road.
He said if Highways England wanted to ensure development did not go ahead without improvements it should have given the junction critical infrastructure status.
"Historically, the junction has a poor safety record, with a high number of reported collisions," he said.
"Data shows that there were 47 collisions over the 17 years between 1998 and 2015. This can be broken down into four fatal accidents, eight involving serious injuries and 35 slight.
"In December 2012 the speed limit on the A483 in the vicinity was reduced to 50mph. The most up-to-date collision statistics show that there has been a substantial drop in accident rates. Moreover, there have been no fatal or serious injuries in the four-year period from 2013 to 2016. This represents a significant improvement in safety.
"Whilst any injury accident is regrettable, it is unrealistic to expect any junction to have a perfect safety record. In my view, the frequency and severity of collisions is not significant as a proportion of the overall number of vehicles passing through the junction."
"I do not consider that the proposal would have a significant adverse effect on highway safety at the Maesbury Road junction, or on the strategic road network."
Mr Parker said that while he understood the concern of local residents over traffic and the potential for their hamlet to be used as a rat run, it was evident that this was a pre-existing problem.
"Whilst the appeal scheme may result in some increase in traffic through Weston, this is unlikely to be the primary means of access and only a small proportion of garden centre customers would use this route."