10 Plants You Should Never Grow Near Apple Trees

Growing flowering herbs, annuals, perennials, and cover crops such as clover beneath apple trees attracts pollinators and helps apple trees fruit better. But while many edibles and ornamentals make good companions for apples and other fruit trees, some plants just don't belong in your backyard orchard.

To avoid apple tree diseases like fire blight and rust and encourage your apples to fruit as well as possible, here are 10 plants to never grow near apple trees.

1. Black Walnut

Black walnut trees may be great for foraging the tasty nuts, but they release a compound known as juglone into the soil to reduce competition from neighboring plants and trees. Juglone is toxic to apples and other fruit trees, and it can cause apples to develop yellow leaves, stunted growth, poor harvest yields, or even die away.

To avoid this issue, keep apple trees at least 60 feet away from black walnuts. Don’t use mulch made from black walnut wood, leaves, or nuts near your orchard.

2. Eastern Red Cedar and Juniper

Eastern red cedar and other plants in the juniper family potentially spread cedar apple rust. This disease involves two hosts: apples or other plants in the Rosaceae family, which include crabapples and serviceberries, and, as a second host, red cedars and junipers. The fungus affects the health and productivity of apple trees.

Initially, affected apple trees exhibit orange or yellow splotches on their leaves. These splotches eventually turn into tube-like structures that spread over affected apple leaves. To manage the disease, grow apples and closely related plants at least a few hundred yards away from junipers, eastern red cedars, and other host plants.

3. Hawthorn

Hawthorn trees and apple trees both belong to the Rosaceae family and are so closely related that they are prone to many of the same pests and diseases. In particular, fire blight readily spreads from hawthorns to neighboring apples, as well as pear trees, and causes these trees to drop their blossoms, stop fruiting, display wilted stems and leaves, and develop other problems. Growing hawthorns far away from apples and pears reduces blight issues. Another way to avoid it is to select apple tree varieties that are naturally resistant to blight and other common diseases.

4. Nightshades

Tomatoes, potatoes, peppers, and other plants in the nightshade family don’t make good neighbors for apple trees either. This is because nightshade plants of all sorts can harbor blight and other fungal diseases that are potentially transmitted to apple trees and closely related plants, like hawthorns.

5. Brassicas

Broccoli, Brussels sprouts, cauliflower, and other plants in the brassica family are heavy feeders that require a lot of nutrients to grow. Planting these crops too close to apple trees deprives both brassicas and apple trees of nutrients and leads to stunted plants and poor crop yields. If you have a limited garden space and still want to grow brassicas near apples, keep your brassicas in roomy planters or pots where they won’t compete with apples for nutrients or space.

6. Root Vegetables

Potatoes, carrots, beets, turnips, and other root veggies require deep soil to grow. If planted too close to apple tree roots, they may become stunted or deformed. On top of that, harvesting root veggies may disturb apple tree roots. Apple trees also cast too much shade for root veggies to grow well.

Whether you plant root vegetables in garden beds, roomy pots, or raised beds, locate them far enough away from your apple and other fruit trees so that your crops still receive plenty of light.

7. Fennel

Like black walnuts, fennel plants release allelopathic compounds into the soil to reduce plant competition. Fennel that is planted too close to apple trees may impact your fruit harvest.

That should not deter you from planting fennel in your garden; just plant it by itself in pots or grow bags. If planted at a safe distance from apple trees, allowing your fennel to bloom even has beneficial effects on apples because it attracts vital pollinators in.

8. Sunflowers

Sunflowers are heavy feeders that compete with apple trees for nutrients and make apples less productive. They also release allelopathic compounds into the soil, which can affect the growth of neighboring plants, including apples.

On the other hand, sunflowers are also highly attractive to beneficial insects, including predators such as assassin bugs that help control insect pests. Make sure to plant the sunflowers away from apple trees to avoid interference.

9. Gardenia

Gardenias are famed for their fragrant flowers, which usually come with petals of pure white, but may bloom in shades of pink or red too. However, gardenia blossoms are highly sensitive to ethylene gas, which apples release when they get overripe. If you grow gardenias too close to apple trees, ethylene gas can spoil gardenia flowers quickly and cause those precious petals to turn brown and wilt before you get a chance to enjoy them.

10.  Turfgrass

While it is not problematic to plant turfgrass around apple trees (a common practice in apple orchards), it is best to keep it at least a few feet away from the tree trunks. Allowing grass to grow directly against apple trees increases moisture issues and the risk of rot as well as mowing or weed-whacker damage. Grass growing up against tree trunks also potentially attracts pests like voles that may nibble on the apple tree bark.

Apply a thick 2- to 4-inch layer of mulch around the base of apple trees to keep turfgrass from reaching the trunk, and keep the mulch 3 to 5 inches away from the trunks of young trees and 8 to 10 inches away from mature trees so it does not cause the apple tree bark to rot.