This page chronicles my own backstory for Bushroot, based on what we saw in canon and drawing my own inferences and expanding from there. This is what I have in mind when I write him. I try not to contradict canon anywhere, although with things that are open to interpretation, there may well be differences of opinion.
Reginald Bushroot was 32 when he was mutated, looking older than his years from a combination of unfortunate early male pattern baldness (like that poor guy I knew in college who was well on his way there at 21), poor posture, and a general inattention to things like regular workouts or healthy eating. Although he had his greenhouse and that kept him busy and somewhat active, it hardly made him athletic. His slouch worsened over the years due to his shyness and the low self-esteem that came through years of being considered nerdy by his peers.
He's the older of two children hatched by Reed and Mary Bushroot, a typical suburban duck couple. His father is a bit of a workaholic and his mother has always been a traditional stay-at-home-mom type. She loves to garden and grow plants, and it was through his mother's enthusiasm that Reggie developed his interest in plants and botany. A genius, Reginald Bushroot always did exceptionally well in school and excelled in the sciences. His favorite studies were the biological sciences, especially ones involving botany. Ironically, his good marks in school and low-key manner always led his parents to urge his younger sister, Heather, to be more like him. Heather, three and a half years younger than Reggie, was not a terrible student and didn't get in all that much trouble, but her grades were average and she had more of an active social life. While not one of the "popular" types either, Heather never had a shortage of friends and her open and friendly nature always tended to draw others to her more so than her older and far more introverted brother. Eventually Heather became a nurse and she and Reggie had a fairly amiable relationship, although that deteriorated after he became a plant-duck super-villain.
Reginald Bushroot acquired his undergraduate and doctorate degrees at St. Canard University, and went on to work there as a researcher in the Botanical and Food Sciences department, headed by Dean Tightbill. He worked there for several years, eventually meeting Rhoda and having the misfortune to have to share lab and office space with Dr. Gary and Dr. Larson as well. The four of them were crammed into one office for their desk work (the boring stuff they couldn't do in the labs) due to the university's cheap budget, which made Bushroot miserable when it came to dealing with Dr. Gary and Dr. Larson, but happy as far as being around Rhoda. He and Rhoda were fairly friendly, and she knew that he had "a bit" of a crush on her, although she had no idea how deep his feelings ran. She thought Dr. Bushroot was a kind and sweet, if not shy, duck, and admired his innovative thinking and his research.
He bought and maintained the greenhouse and its large lot with the lion's share of his earnings as a researcher. Prior to his mutation he did not live there, however, and kept a small and cheap apartment nearby. He gave that and his old beater car up when he became a plant-duck and an outlaw, and moved into the greenhouse full time.
After the events in Beauty and the Beet took place, Bushroot spiraled into a cycle of depression, loneliness, and greedy self-destructiveness. It only got worse with the disastrous fiasco with Posy, and the other canon episodes. One of his lowest points of misery was the events seen in It's a Wonderful Leaf, which took place after a miserable Thanksgiving encounter with his family that I wrote out in Thankless Season. Although I have some divergent storylines that cannot happen in the same universe, pretty much all of them consider the events of that story to have occurred.
Bushroot agreed to join up with the Fearsome Five when Negaduck invited him partly out of greed and partly out of a desire to belong somewhere. In his time with the Fearsome Five, he formed a friendship with Liquidator, who he partnered with often. He can take or leave Megavolt and Quackerjack, depending on how they treat him. He would gladly befriend them if they showed interest in doing so, but Quackerjack scares him somewhat and he finds Megavolt moody, so they remain friendly acquaintances for the most part. Bushroot does not really like Negaduck, mostly because Negaduck makes no secret of the fact that he hates him and the others on a personal level, and because of his constant threats. Although Negaduck would be hard-pressed to actually kill Bushroot considering his rather durable form as a plant-duck, things like mulching that he can recover from are still quite painful. Also, Negaduck made it clear to Bushroot that if he ever crossed him, he would burn down his greenhouse and all of his plant friends in it after putting him out of commission. Between that and Bushroot's naturally submissive and fearful nature, he does not argue with Negaduck and takes his threats seriously. Still, Bushroot respects Negaduck's strength and is not above using an alliance with him to his benefit, and has the attitude of "the enemy of my enemy is my friend" about him when it comes to Darkwing.
Other random facts about Bushroot that I incorporate into my stories:
His astrological sign is Libra, with a birthday in October. I base this on a number of criteria: his bouts of indecision, his quest for a partner and marriage, his attention to fashion (seriously, Libra men are the types who would pick out their bride's dress for them or ask a saleswoman what color is best), his incredible ability to rationalize, and his initiative in taking action once he decides to do it. I also think he has a Taurus influence somewhere, most likely rising given his pre-mutation stature and solid (albeit wimpy-solid) build and love of nature and plants. Also, Taurus is a sign that's slow to anger, but when it does, watch out. Raging bull all the way.
His pollen is viable, and can fertilize certain flowers in the same family as Lyceum nycanthropus. He knows because he tested it. The results aren't sentient plant-children, however, but flowers that seem like they were genetically engineered with duck DNA on a very advanced level. (Feathery petals, stems made of the same tissue as a duck bill, stuff like that.) His pollen is also viable with ducks, although he hasn't been brazen enough to kidnap a female duck just to test that. He wants to find one that loves him before he'd try to make any little seedlings with her.
Bushroot does not need to eat food, although he can if he chooses. He does better with fertilizer, and some food works similarly, but he can subsist on sunlight and water alone. He prefers to not go without his morning fertilizer coffee, though! In regards to water, he needs it like any plant does, and he'll wilt more easily in hot and dry temperatures.
Bushroot's greenhouse has some basic amenities that he added when he made it his permanent residence, including a kitchenette in the room-like part of it in the back where the bathroom also is.
Nega-Bushroot started out as a real jerk, and lost his job at the university because Dr. Gary and Dr. Larson, who were actually nice guys in the Negaverse, paid him back for years of verbal abuse and back-stabbing in the workplace. Nega-Reggie also had a torrid relationship with Nega-Rhoda, who is an ambitious schemer and opportunist. In the Negaverse, she was at his side when he mutated himself, and wanted him even more once he gained his powers. After he killed Dr. Gary and Dr. Larson out of spite, however, Nega-Bushroot felt his first stirrings of guilt and took a harsh look at himself and how he was living his life. He realized that it wasn't in him to be a killer, which infuriated Nega-Rhoda, who wanted him to use his powers to get whatever he wanted and ally with Negaduck. Once it became clear that wouldn't happen, and that he would not share his newfound powers with her by mutating her into a plant-duck like him, his relationship with Rhoda soured, and she spitefully turned on him for spurning her.
Also, in the Negaverse, Nega-Bushroot's family is ashamed of his alternate self, but for what they consider "crazy" acts as hardened Negaverse personalities. Nega-Heather is a nurse like her counterpart, but rather than having her compassionate nature, she's selfish, whorish, and self-destructive. She's also addicted to narcotic painkillers, which eventually cost her the job she held as a nurse for stealing them.