Every species that grows in the garden, in the order you will meet them. Once you have grown one, it gets its own page in the in-game Flowerdex too.
Flowers are what turn the garden from a pile of paw prints into something that grows. Plant one in an empty pot and it takes a few seconds to come up; after that it makes pollen for as long as it stays planted. Pollen buys some of the supplies, and above all it feeds the bees, which turn it into honey.
Every species gets a little more expensive with each copy you plant. Early on that barely matters. Later it is the reason to move on: when a tenth daisy costs more than a first tulip, the tulip is the better buy. Rarer species take longer to grow but produce far more.
A planted flower can be looked after to raise its tier, and each tier makes it more productive. There are four, and the flower's name changes to show which it has reached:
Radiant is the ceiling. Past that, more pollen comes from another pot or a rarer species rather than from one more round of care on the same daisy. The Watering Can makes every flower grow faster, and cats with the Green-Pawed trait tend flowers on their own, which makes those flowers produce much more.
Cheerful, unbothered, everywhere.
The first flower in every garden and the cheapest. It grows in a few seconds and makes a small, steady trickle of pollen — enough to get the tulip unlocked and the first bees interested.
Opens and closes with the light. The cats find this suspicious.
Several times the daisy's output for a correspondingly higher price. Tulips are what carry a young garden to the 150 pollen that brings the bees.
Dramatic. Thorny. Worth it.
The flower of the mid-game. A bed of roses is what lets the hive grow big enough for honey to start adding up, and honey is what the later cats are bought with.
Tall enough that Biscuit has tried to climb it. Twice.
The first flower a first garden cannot reach. It is there to make the second run feel different from the first: bigger, slower to grow, and worth dozens of roses.
Only blooms for cats who have already dreamed twice.
The top of the flower ladder. It takes the longest to grow and makes the most pollen by far. Having grown one is also part of what the very last cat is waiting for.
Usually the newest species you have unlocked, as soon as you can afford it, while keeping the older pots full rather than digging them up. When a species' next copy costs more than the first copy of the one above it, stop buying it. And spend a little on care: a Radiant rose is often a cheaper improvement than yet another pot.