From Bulbapedia, the community-driven Pokémon encyclopedia.
The Celadon City Flower Bed Deck is a type deck found in the Gym Heroes Strategy Guide. The deck is classified as one of the advanced decks, containing more rare cards and strategy than other easy-to-build decks.
Celadon City may be a beautiful place, but it can be dangerous for decks that aren't ready for it. The focus of this deck is Erika's Gloom. Use its Dream Dance and Vile Smell attacks to Confuse and make your opponent's Pokémon Asleep. Gloom's attack has the same effect on itself, but you can use the Celadon City Gym to keep "Full Healing" Gloom over and over again as long as you have enough Energy. Erika's Maids can help make sure you get Erika's Gloom when you need it—as can Bill and Professor Oak.
Your other Pokémon can Poison your opponent's Pokémon for yet another way to to cause them problems. If you can get Erika's Vileplume out, your opponent is really in trouble. Vileplume's Pokémon Power: Pollen Defense Confuses attacking Pokémon, while the Mega Drain removes damage counters from Vileplume (and adds some to the Defending Pokémon!)