8 Plants You Should Never Grow Next to a Lemon Tree

Black Walnut Tree

Planting a black walnut tree next to a lemon tree will cause one or both to suffer. They produce a chemical toxin called juglone, which can stunt or ultimately kill a lemon tree, says Tammy Sons, CEO and founder of TN Nursery. Juglone is unsafe for many other plants, too, including hydrangeas, so be careful when planting anything near a black walnut tree.

Fennel

Don’t plant fennel near lemon trees. “It has allelopathic properties that inhibit any type of nearby plant growth,” says Sons. Like black walnut trees, this is another plant that you probably should be careful about including next to other garden varieties—there are many plants you should never grow next to fennel.

Brassicas

This family of plants includes cabbage and mustard, and while they can grow next to lemon trees, they might not make the best garden bedfellows.

“Brassicas compete with other plants for nutrients and can attract harmful bugs,” says Sons. Cabbage worms and cabbage loopers, for example, are common garden pests attracted to these plants; they can also damage nearby plants.

Conifers

These evergreen trees are great for many woodland gardens, but they don’t do well beside a lemon tree. “Conifers have acidic needles that can alter the pH of the soil as well as compete for water,” says Sons. So don't grow lemon trees and conifers too close to each other.

Olive Trees

Olive and lemon trees can get some of the same diseases, including root rot, canker, and anthracnose. According to Sons, it’s never a great idea to plant these trees next to each other.

Root Crops

Root vegetables like potatoes, carrots, beets, and turnips make for poor garden bedfellows for lemon trees. To harvest these root crops, you have to dig them up, and lemon tree roots are shallow and grow near the soil’s surface—harvesting root veggies might inadvertently harm your lemon tree.

Orange Trees

Orange and lemon trees are actually great companion plants. However, if your soil is on the arid side and poorly draining, avoid pairing these two—both require about 2 inches of water per week to thrive.

Mint

Mint is notorious for filling up a flowerbed and spread throught a garden. As a result, this plant will compete too much with a lemon tree—or any fruit tree, for that matter. Mint does well as a potted plant, however, according to Sons.