I think we have plenty of trees and plants from the tropical and desert regions, but we still don't really have enough variety in plants from the temperate, grassland, and taiga regions. Because I'm American, a lot of these picks will obviously be more local to where I live since that's what I'm familiar with. I apologize if this list is very heavy on the North American temperate plants, that's kind of just how the cookie crumbles.
Conifers:
First of all, I think the game needs some more conifer variety, for both the temperate and taiga biomes. There could definitely be more variety in tree species from these biomes, and there's a lot of interesting conifer species that Planet Zoo is lacking.
1. Norway Spruce (Picea abies) - Native to colder parts of Europe, the Norway Spruce is also widely planted elsewhere. They offer great shade and can grow quite tall.
2. Colorado Blue Spruce (Picea pungens) - As the name implies, this species is native to parts of the Rocky Mountains, namely Colorado. However, it's also commonly planted throughout the United States. It is most notable for the blue color of its needles.
3. White Spruce (Picea glauca) - This large species of spruce is native to the northern temperate and boreal forests of North America. It has a wide range throughout northern North America. It should not be confused with the Colorado Blue Spruce, which is sometimes also called White Spruce.
4. Lodgepole Pine (Pinus contorta) - A very common and widespread tree throughout western North America. It has also been planted elsewhere for timber uses.
5. Common Juniper (Juniperus communis) - A small tree or shrub, the Common Juniper has the largest geographical range of any woody plant. It is widely distributed throughout the Northern Hemisphere.
6. Tamarack Larch (Larix laricina) - This is a unique tree because it's a conifer that changes color in the fall and sheds its needles. It is common throughout the taiga and northern temperate regions of North America.
7. Eastern White Pine (Pinus Strobus) - The Eastern White Pine is the tallest tree species native to the temperate regions of eastern North America. This species is abundant where I live, and they’re very beautiful trees. This species is also planted as an ornamental tree in gardens and parks.
8. Longleaf Pine (Pinus palustris) - A pine species native to the southeastern United States, found along the coastal plain from Texas to Virginia. This is an endangered tree species, so it would’ve been a fitting addition to the Conservation Pack.
9. Italian Stone Pine (Pinus pinea) - This tree species is found in the Mediterranean region, specifically in southern Europe and the Levant. It has been cultivated elsewhere as well. This tree would fit well in our European sections of our zoos, and it would've fit in well in the Europe Pack.
Autumn Foliage Trees and Bushes:
Another thing Planet Zoo is lacking is good autumnal foliage. There's only a few autumn foliage trees in the game currently, which makes things difficult if you're trying to do a seasonally-themed zoo.
1. Red Maple (Acer rubrum) - Widespread in the eastern United States, and commonly planted as a shade tree elsewhere. This species has really spectacular fall colors, turning bright red in autumn. It would be perfect for an Autumn-themed zoo. I'm honestly quite surprised that this species isn't already in the game.
2. Shagbark Hickory (Carya ovata) - This species of tree is common where I live. It can grow over 100 feet tall, and can live more than 350 years. The outer bark often hangs off of the mature trees in strips, giving them a rugged appearance. In autumn it has beautiful yellow foliage.
3. Northern Red Oak (Quercus rubra) - Another species native to the eastern and central United States, including the area where I live. This oak species has really nice dark red foliage in late autumn, which adds a really beautiful splash of color to the landscape.
4. Eastern Cottonwood (Populus deltoides) - There's not many trees in the North American grassland biome in Planet Zoo, which is unfortunate because we have several animals from this region in the game. The Eastern Cottonwood is widespread in North America in both grassland and temperate regions. This tree species would be a great candidate to add a new tree species to this biome and continent combination. It also has pretty nice yellow autumn foliage.
5. Ginkgo (Ginkgo biloba) - Ginkgos have some really nice fall foliage. They are native to Asia, but are also often planted in other places.
6. Red-Osier Dogwood (Cornus sericea) - This deciduous shrub is native to much of North America. Common in riparian areas and wetlands in the wild, it is also a popular ornamental shrub. The autumn foliage ranges in color from bright red to purple.
Other Trees:
1. Silver Birch (Betula pendula) - It would be pretty nice to have some more types of birch trees in the game. The Silver Birch is native to Eurasia and is a very beautiful type of tree.
2. Southern Live Oak (Quercus virginiana) - This tree species is iconic in the southern United States and would be very fitting in habitats for species like the American Alligator.
3. Southern Magnolia (Magnolia grandiflora) - An evergreen tree species native to the Southeastern United States. This species is also commonly planted as a large ornamental flowering tree, both within its native range but also sometimes farther north.
4. Kousa Dogwood (Cornus kousa) - Kousa dogwood, also known as Chinese dogwood, features flowers in spring that make the species popular, making it perfect for a springtime-themed zoo. This plant is native to East Asia including Korea, China and Japan. It is widely planted as an ornamental tree.
Flowers:
1. Lupine (Lupinus)
2. Heartleaf Arnica (Arnica cordifolia)
3. Fireweed (Chamaenerion angustifolium)
4. Common Dandelion (Taraxacum officinale)
5. White Clover (Trifolium repens)
Miscellaneous:
Common Snowberry (Symphoricarpos albus)
Those are all of the plants I would consider to be essential. There are others that I’d like to see added, but they're not as important in my opinion. I mainly wanted to post this list here so that I’d have it written out somewhere.
