Alright, I hope this passes muster, here is my SU.
Side: Gold
Name: Dinorah
Gender: Female
Age: 18
Title: None
Pokemon Species: Meganium
Appearance: She mostly looks like a fairly standard Meganium, but since her father is a Venusaur, she has picked up a few bits of her appearance from him. Her skin is a slightly darker green, the flower petals at the base of her neck have small light pink splotches randomly dotted across them, and there are darker green leaves behind the flower petals, providing a little extra support. She also has reddish eyes like a Bulbasaur which haven't changed in color since she was a Chikorita.
Personality: While her wanderlust has faded a little from when she was younger, Dinorah still loves to see new places and meet new Pokemon. This has been rather hard for her to deal with since the invasion, having to stay in hiding all the time while her family keeps to themselves mostly for fear of being discovered by the Silver Tribe. However, the safety of her family is still much more important to her than any desire to go for a stroll through an open meadow or city full of other Pokemon. The recent events with the Silver Tribe have made her more wary around anyone she knows nothing about. However, if you do earn her trust, you will have a friend for a lifetime. She will fiercely defend her friends and allies if needed, and has the training and abilities to do it.
History: Dinorah was born in Shine City, raised by two happy parents, a Venusaur named Soto, and a Meganium named Ayanna. She would eventually come to have a younger brother and sister as well. As a young Chikorita, she was very adventurous, often slipping away to go exploring on her own. Punishments didn't seem to do anything to curb her enthusiasm, so her father decided to start teaching young Dinorah all he knew about combat in the hopes that if she did find herself in a dangerous situation, she'd be better able to defend herself.
As she grew older, and her abilities grew stronger, something new drew her interest, and she began to dream of joining the Gold Tribe when she was old enough. She envisioned herself traveling around Valkaria, seeing lands far beyond the area of her home as he helped with missions of all sorts in service of the Alpha Alliance. With this new goal, she only trained even harder, and before long she had evolved into a Bayleef and learned just about everything her father could teach her. So she sought out training from others in the city that had more battle experience.
Some years later, shortly after her sixteenth birthday, Dinorah decided she was as ready as she'd ever be. It was time to attempt to join the Gold Tribe. Alas, she would not get her chance, as it was when the invasion of the Silver Tribe came. Her whole family attempted to flee together, with her father attempting to slow down the advancing Ancients , while she, her mother, and her siblings made their way out of and away from the city. There were just too many however, as soon they lost sight of Soto, and found themselves surrounded. With the situation looking rather bleak, suddenly something miraculous happened. The deep, heartfelt desire to help her family escape combined with how dire things had become, triggered Dinorah to evolve. She and her mother fought with everything they had, and somehow managed to break through the net of Ancients closing in around them, and from there, they ran for their lives, making for the deep forest in the hope that it would hide them well enough that they would be able to escape. They never saw Soto again after that day.
Dinorah has been living with her mother and siblings in the forest ever since, constantly staying on the move in the hopes that it will help them avoid discovery and capture. Recently however, her brother, the second oldest after her, has grown to be old enough to fend for himself and help Ayanna take care of his sister. They have also been in contact with a few of the scattered groups of Pokemon not loyal to the Silver Tribe. They have heard tales that the Gold Tribe still exists and is fighting to take the land back from the Silver Tribe. So, knowing that they can't hide in the forests forever, particularly if the Silver Tribe succeeds in wiping out all other resistance to their rule, Dinorah decides to leave her family and seek out the remaining members of the Gold Tribe.
Moveset: Solar Beam, Vine Whip, Light Screen, Reflect, Aromatherapy, Synthesis