Castiel is the first to discover that the bunker has a greenhouse. No one should have been surprised really, between the dungeon and the observatory, and to be fair Dean and Sam could be forgiven in their failure to find it by the fact that it wasn't so much in the bunker as outside behind it, accessible only by a small, nondescript door down a forgotten hallway, opening onto rickety, rusted steps leading to the surface.
The space itself is pretty dreary. The bunker had been abandoned in haste, after all, and so all the plants within it had been left to die, rot, or mysteriously overgrow despite the seeming lack of any irrigation, making the greenhouse look less like a greenhouse than a barely contained jungle, that smells like something across between putrefying compost and some sort of flowery pollen that makes Castiel sneeze as soon as he enters it. His unfortunate discovery of some kind of allergy aside, Castiel immediately takes a liking to the place.
Perhaps it is something about the wildness of the room, reigned in only by the glass enclosing it, that makes him think that mysteries and miracles of growth can still exist even in the most forgotten of places. Or maybe it's that the greenhouse, down its small corridor and up its broken steps, in all its chaos continues to exist in stark contrast to the clean order of the rest of the bunker. Suffice to say, it has a curious sort of character, and Castiel is intrigued by it.
When he first stumbles onto it, he has the idea to clean it up. Prune back some of the more enthusiastically grown vines and branches that make walking about the room difficult, remove some of the more pungent culprits of compost from their swampy corners to make the air more enjoyably breathable, but something in him stalls the pace of his renovation only thirty minutes after he begins it. Standing amidst the overgrown garden of his discovery, hands caked in dirt and body caked in sweat from the humidity, Castiel realises he doesn't want to curve the verdant chaos of the greenhouse at all, but rather encourage it.
Clipping back the leaves and trees that managed to grow in this tiny corner of the world without watch or care would be a sort of cruel reward for their resistance, he thinks.
So instead, he sets about improving the conditions. First, he finds out where whatever water and air that has clearly been feeding the flowers of this place has been coming from all these years, and makes it flow in earnest, tinkering with the pipes of a long unused irrigation system to bring it back to life. He opens the ventilation, sweeps what floor might need to be swept, a this goes on for hours upon hours until Dean finally finds him, late into the afternoon.
"Jesus Christ, Cas, I was beginning to think you'd ran away or somethi--" Dean starts to greet him with, until he actually takes in the sight of Castiel standing in the middle of the room, up to his elbows in dust and dirt and hair in even more disarray than usual, and is halted in his tracks. "Oh my god," he says instead, "you've transformed into the Troll from Central Park."
Castiel frowns in his typically endearing way, which makes Dean's formerly worried expression transform into a grin. "I'm sure that's another movie reference I remain ignorant of."
"Ah, you'll catch up," Dean waves off, stepping over some stray hoses as he comes closer. He looks his friend up and down. "Fuck, you're filthy. Is this what you've been up to all day? Digging in a jungle?" he asks as he peers around.
Castiel bends down to pick up a shovel that he had found, forgotten in a closet. "I was under the assumption you like it when I am filthy," Castiel deadpans, and Dean coughs as he blushes, gaze fixed on where Castiel's ruined t-shirt rides up his back when he leans down.
This thing between them is still new yet, much like Castiel himself, in a way, human like this. It's something they've in equal parts sharply stuttered and slow danced into, after all those years struggling to find the right steps. Someplace inside his chest still aches like a lonely cavern, but on days like this, with Dean's smile in his sight, Castiel takes a deep breath and revels in the way the sunlight hits his skin.
"But yes, I've decided to grow a garden," he explains.
"Looks more like a forest than a garden in here," Dean comments idly as he steps around Castiel to look around a bit more.
"It is a bit untamed, as expected after decades of neglect. This area is very promising, though," Cas says as Dean turns back around, pointing at the patch of earth he's cleared. "I'd like to grow some flowers."
Dean smirks. "Aw, if you wanted flowers, Cas, you only had to ask."
Castiel offers a twitch of a smile in return. "I much rather be romanced with coffee from you, thank you," he half-jokes back, for he actually really would rather coffee. "No, I'd like to grow them on my own. Some herbs too perhaps," he adds before he pauses. "Lavender," he comments more to himself than anyone. Something in its scent smells pure, he thinks, but honest in its derivation from the dirt, like little purple new beginnings.
"How long do you think it'll take?" Dean asks as he walks back towards him.
"Awhile," Cas answers honestly, looking forward to the distraction of work to be honest, to busy his hands with creation for a bit. He looks at Dean then, traces the freckles along his nose with his gaze. He smiles back. "But I have awhile, don't you think?"
"Yeah," Dean says thickly, hand coming up to cup Castiel's face, who leans into the touch. Dean squints slightly as he rubs a thumb across Castiel's cheek, bringing his hand back to show Castiel the dirt he managed to take off with a laugh. He raises his brow suggestively. "Shower first though?"
Content with his progress here for the day, and tempted by Dean's too brief touch, Castiel obliges.
The next morning Castiel steals out of bed early to begin work again. Hours later after breakfast, he's joined by Dean, who brings him coffee, and a small paper package of something Castiel discovers is full of seeds when Dean places it in his hand. They're lavender.