Chicken-Friendly Backyard Landscaping

Lots of you raise backyard chickens that are allowed to roam your backyard, either supervised or unsupervised, and might wonder if your existing landscaping is okay if your chickens happen to nibble on it (which they are prone to do!).
I'm frequently asked what kinds of plants, bushes and trees are safe to plant around chickens.
In addition, I'm often asked for a list of vegetables and herbs that can be planted in the garden that are safe for chickens to eat and a list of things that aren't safe.
For the most part, anything you plant for your family will generally be safe for your chickens, with a few notable exceptions being anything in the nightshade family - ie, tomatoes, eggplant or white potatoes - or things in the onion family.
As far as herbs go, the culinary herbs are generally safe for your chickens, although there are other herbs that can be harmful. But I haven't seen too many lists of other types of plants that you might either already have in your backyard, or be thinking about planting in your backyard, so I've done some research and come up with some "safe" lists and then some plants that might pose a problem for your chickens.
Many of these "toxic" plants appear on lists of plants that are toxic to livestock in general, not specifically chickens, but as always I would rather err on the side of caution. Usually chickens (and other animals) know enough to stay away from anything that could be toxic, so while I wouldn't go ripping out your entire oleander hedge for example, I wouldn't go out of my way to plant anything near your coop or where your chickens wander that could be dangerous if they were to eat it. Typically, animals provided adequate nutrition in their daily diet won't eat foliage, leaves or seeds of potentially harmful plants, but sometimes out of curiosity or boredom, they may just decide to nibble on something they shouldn't.
One interesting factoid: nothing in nature that is poisonous actually tastes good. But still...why take you chances? Bored, hungry or young birds might get just a bit too curious.

What's Safe for Chickens?
Safe plantings for your yard include...
Bushes/Shrubs
In addition to berry bushes, there are lots of other types of bushes that your chickens can enjoy without worry. Our ducks especially like to nap under the various bushes in our yard.
Beautyberry (Callicarpa) Blackberries Blueberries Butterfly bushes Hawthorn Hosta Juniper Lilacs Raspberries Roses Flowers
There are a great many edible flowers that can be enjoyed by your chickens. Edible flowers also make wonderful drink or dessert garnish!

Baby's Breath

Bachelor Button

Bee Balm

Borage

Calendula

Chamomile

Coneflowers

Daisies

Dianthus

Echinacea

Hollyhock

Lavender

Mallow

Marigolds

Pansies
Peonies

Petunias

Pineapple Sage

Roses

Salvia

Snapdragon

Sunflower

Sweet William

Violets

Yarrow

Zinnias

Trees
If you are considering adding a few trees for shade in your yard or around your chicken run, these are good choices.
Alder Ash Aspen Birch Evergreen Fig Hazelnut Hickory Magnolia Mimosa Mulberry Palm Pecan Poplar Spruce Sycamore Vines
Vines trailing up the side of a chicken run provide wonderful shade from the sun as well as a bit of a wind block. There are some of my top choices.
Green Beans Cucumbers Grapes Honeysuckle (flowers and nectar are safe, but stems, vines and berries of some varieties are toxic, some aren't, so do some research first) Jasmine Morning Glory (the seeds of some varities are toxic, so check before planting) Nasturtium Peas Roses Squash

So What's Not Safe?
The list of toxic plants is extensive and should by no means be considered to be listed in its entirety here.
I have merely tried to list some of the more common things that you might consider planting in your yard and caution you that they could have harmful effects on your chickens.
Steer clear of...
Bushes/Shrubs
Not all shrubs are safe for your chickens. While I wouldn't necessarily pull them all out of my yard, I wouldn't deliberately plant any of these around my chickens.
Azalea Bleeding heart Boxwood Bracken fern Burning Bush Elderberry Eucalyptus Hemlock Holly Hydrangea Mistletoe Mountain Laurel Nandina Oleander Philodendron Rhododendron Wisteria Flowers

Many bulbs are toxic to animals and appear on this list of flowers to avoid.

Amaryllis

Belladonna

Buttercup

Chrysanthemums

Daffodil

Delphinium

Hyacinth

Iris

Jack in the Pulpit

Lantana

Lily

Lupine

Milkweed
Narcissis

Nightshade

Poinsettia

Poppy

Tulip

Trees
Many trees can pose a problem as far as the dropped fruit/leaves/seeds are concerned. Here are some examples of trees to think twice about before planting them around your chickens.
Apple (seeds contain cyanide) Apricot (pits contain cyanide) Avocado Box Elder Cedar Cherry (pits contain cyanide) Chokecherry Citrus (Lemon, lime, orange, grapefruit) too much citric acid can result in soft-shelled eggs Eucalyptus Horse Chestnut Red Maple Oak Peach (pits contain cyanide) Plum (pits contain cyanide) Sumac Wild cherry Yew

Vines
Not all vines are safe. Here are some to avoid around your chickens.
Castor bean Clematis Honeysuckle (see above, it depends on the variety) Ivy False jasmine (Carolina or yellow) Morning Glory (the seeds of some varieties are toxic, so check before planting) Poison sumac Trumpet vine Virginia creeper

Many of the toxic plants listed above are also toxic for humans, cats and dogs as well, so sticking with some safer options is generally better all around. Here's a really good, comprehensive list of plants and their toxicity.
At the very least, it's a good idea to be able to identify toxic plants, so if you suspect poisoning, you might be able to narrow down the possible culprit to notify your vet. If you do suspect any type of poisoning, administering some blackstrap molasses or activated charcoal can work as a natural detoxifier and help flush out any toxins before you can get to a vet.

Note: Remember that while chickens do a pretty good job at deciding what's okay to eat, letting them free range poses risks that they will ingest something that's not good for them, including any lawn or plant treatments you might use including fertilizers, herbicides or pesticides.
I personally recommend refraining from using any chemicals on your property if you raise chickens. It's healthier and safer for your family and other pets too.