This mod also adds some new structures in the new biome!

Bloom Ruins, a new structure that spawns in the Giant Flower Plains:

The Titan Bloom, a rare structure in the new biome:

New blocks: 

Herios' Floral Expansion adds tons of new blocks, including a new type of Flower Pot, the Big Flower Pot, essentially a Flower Pot the size of a normal block (it's actually a pixel taller but you get it).

Some of the new blocks are the Chlorophyll lamps, lanterns, polished pillar, Chlorophyll Brick and Polished Chlorophyll Brick sets, all shown below:

You can get the chlorophyll by cutting the stem of a giant flower with some shears. After some time, the cut stem will start dripping chlorophyll and you can collect it with an empty bottle.

Flower Pots:

You can craft two new types of Flower Pots, the Big Flower Pots, and Bonsai Pots:

You can also craft Big Decorated Flower Pots with the stonecutter, but there are 4 special designs, The Ancient (Sniffer), The Sentinel (Elder Guardian), The Winged (Ender Dragon), The Protector (Warden), and The Wilted (Wither) which you can only craft using special ingredients from said mobs (Sniffer Egg for its design, for example).

Big Flower Pots and some of their designs:

A torchflower in a big flower pot:

Some big flower pot designs:

Bonsai and their pots:

You can get the new Bonsais by using shears on a sapling of your choice (it looks a bit goofy on mangroves tho), and then you can place them in the Bonsai Pots.

Some Bonsais placed in their pots:

New wood: 

Alongside the new biome, you can get two new sets of wood, the Giant Stem set and the Dried Stem set. You can chop the giant stems from the giant flowers like a normal tree and dry them in a furnace:

The Giant Flowers contain pollen of course, this new block is called Pollenlight, an overworld version of the Shroomlight. You can also get the Petal Blocks with a hoe and you can dye them to get a specific color or craft them into 2 dyes of their respective color!

All types of Petal Blocks:

You can also brush the Pollenlight blocks to get Luminous Pollen, this new item can be applied onto Petal blocks to make them glow! You can brush it off of Luminous Petal blocks too.

Mud Road: 

This new block crafted from 2 Mud and 2 Cobblestone is used to make Bogwalkers (a new mob) faster. You can paint a little white line with White Dye, Light Grey Dye or Bonemeal for decorational purposes:

Bloom:

These little two-legged flowers have many color variants! They can be found roaming in the Giant Flower Plains and the vanilla Flower Forests with a low chance. The Blooms can be fed bone meal to drop seedlings, which allows you to grow them wherever you want. You can also dye them any color!

Bambloom:

The jungle cousin of the Bloom! These critters inhabit Bamboo Jungles. You can use Bonemeal on them to get their seedlings! Bamblooms can have 3 different sizes; They can spawn naturally with any of the sizes or you can use Water Bottles to make them grow into the next stage!

All Bambloom sizes.

Dry Bloom:

These Bloom husks wander around in arid biomes. If hit, they have a chance of dropping a stick.

Cattus:

The Cattus are a species of cat-like critters made out of Cactus. You can tame them with Bonemeal and take them as mascots. They are immune to cactus damage and can lie down if tamed and right-clicked. They'll also attack Creepers, insta-killing them.

Some Cattus lying on the ground and cactus.

Bogwalker:

The gentle giants of the Mangrove Swamps. The Bogwalkers are tall creatures with long legs and a solid hitbox. They can be tamed with Bonemeal and rided if you give them a saddle, which will also give the Bogwalker an inventory (due to MCreator limitations you can access the inventory only by shift-right-clicking).

A tamed and saddled Bogwalker.

Lush Bats:

These are simple ambient mobs. If a Dynamic Lights mod is installed, they will glow.