In estates across Belfast, in community gardens, even in the Mourne Mountains, trees have been appearing overnight.
And much of it is the work of a mysterious figure, an environmental superhero who calls himself the 'Phantom Planter'.
Often arriving at the scene unannounced, the Belfast man on a secret mission is now cultivating a cult following for his superhuman efforts in what he calls "environmental graffiti".
He can turn up anywhere there's a plot of open land, but the Belfast Telegraph tracked down the masked crusader to Dundonald, where his latest planting exploits were taking root yesterday.
While not exactly a caped crusader - capes would get in the way of digging and might snag on a branch - the mystery man prefers to keep his identity a secret for now.
"Yes, there might be a bit of mystery to it, but if that's what it takes to get the message out there then no problem, I'll carry on being the Phantom Planter," he said.
"I suppose in my own way I'm trying to save lives.
"Some might see it as a bit of mischief and it does give you a buzz, but there are worse things I could be doing.
"The main aim is to get people to fall in love with nature. It makes people happy, it makes me happy.
"I've been planting trees for years, but now it's taken on a life of its own. I want to get people motivated to look after their own areas and what I've been trying to do is starting to get attention, and that's great.
"It's about doing a bit of good for the community. It's green graffiti, but all with the purpose of making the world a better place.
"I planted my first tree with my own kids five years ago. We go back and pick the apples.
"It's important kids today learn where their food comes from, that trees can give them fruit for years to come, that we can all do a little bit to heal the world we live in.
"Thankfully, most of the councils have left the trees alone. The residents too have embraced them. Some have added their own flowers around them.
"If there's a green space, I'll try to stick a tree in it, and I'd love more people to adopt that spirit."
He admitted he's lost count of how many new trees are growing across Northern Ireland thanks to his efforts.
"I've planted thousands," he said. "I've been secretly planting in the Mournes where it's one of my goals to 'guerrilla plant' my own forest, all native trees to the area. Another 50 went in there at the start of December.
"Around east Belfast I've planted apple trees, Blood of the Boyne. It seems like people appreciate the name and not one of them has been damaged!
"I'll try to breed a new variety of apples and call them Michael Collins. Those will go in around west Belfast!"
The eco warrior said he never thought he'd get such enjoyment from nature before reinventing his life. "I've spent my life as a wheeler dealer, a 'Del Boy' around the city," he said.
"I got into bad habits, I was overweight and the bad side of life was taking me over.
"You could say I had a spiritual awakening. I live in a caravan now, I live off the land as much as I can. I don't drink any more. I do yoga and meditation and get in touch with nature. It's important that kids get in touch with the world around them too.
"Sometime people are taken aback when they see me turn up, but they quickly come round and get involved. I want people to engage with this. At the start I would have bought the trees myself, but now I have a network of people helping by supplying cuttings.
"If there's ever a problem, I have no issue removing a tree and placing it somewhere else. I don't want to cause any problems, but the feeling I get planting trees is wonderful. It always makes me smile, charges my soul and keeps my head in a good place.
The fruits of his labour are already being harvested in Dundonald after his arrival at The Men's Shed in Ballybeen. On this occasion the Phantom Planter appeared by appointment,
"Today we've had the first tree planted in a long-term project for the community," said Ballybeen Men's Motivational Group trustee Mark Brotherston.
"As a group we have plans to work with our local special needs schools at Longstone and Tor Bank for further planting and regeneration. This has given us all a real incentive."
But the hero has the final word. "I challenge everyone to phantom plant a tree. Anywhere, any time, any place!" he said.