Unless you frequent botanical gardens, it’s very possible to have never seen, or heard, of borage. While borage is considered an herb and is edible, it isn’t commonly grown for harvest and consumption. Thanks in part to its bright blue and pink flowers, boreage is really useful in the home garden because it brings pollinators to the plants nearby.
Borage is an underappreciated herb that deserves more attention in home gardens. With its edible flowers and leaves borage can add flavor and color to meals. But its true value comes from being an excellent companion plant. Borage helps nearby plants by deterring pests attracting pollinators, and improving soil nutrients.
However, borage does have a few companions that it should avoid. Planting borage near the wrong plants can hinder its growth and reduce its benefits. Here are the key plants to avoid planting with borage.
Potatoes – The #1 Plant To Avoid With Borage
Potatoes and borage do not mix well. Potatoes are prone to late blight, a devastating fungal disease. Unfortunately, potatoes can spread late blight to borage. The fungal spores travel through the air from potato plants to borage. Once infected, the borage leaves yellow, wilt, and die.
To prevent the spread of late blight do not plant borage anywhere near potatoes. Leave plenty of space between borage and potatoes – at least 20 feet if possible.
While late blight can also infect tomatoes, tomatoes do not spread the disease to borage. So tomatoes can still be effective borage companions. Only potatoes are unable to coexist with borage due to late blight contamination.
Fennel – Keep This Toxic Plant Away From Borage
Fennel is another plant to keep far away from borage. All parts of the fennel plant, including the leaves, stems, and seeds, produce organic toxins. These naturally occurring chemicals hinder the growth of other plants located nearby.
Borage is especially sensitive to the toxins emitted from fennel. When grown near fennel, borage growth is stunted. The leaves turn yellow and the plant may die.
For the healthiest borage, plant it as far away from fennel as possible. Fennel is best grown in a isolated corner of the garden, far from other plants it could harm.
Black Walnut Trees – Dangerous Even After Removal
Mature black walnut trees also emit toxins that suppress nearby plant growth. The tree roots release juglone, a substance that inhibits many plants from thriving within the tree’s root zone.
Even after a black walnut tree has been removed, the juglone residues in the soil can persist for years. Planting borage in an area where black walnuts once grew is risky. The remaining juglone may stunt or kill the borage.
Before planting borage, check your garden for any current or former black walnut trees. You may need to find an alternate planting area or wait several seasons for the juglone levels to dissipate.
Brassicas – Cabbage, Broccoli, and More
While borage gets along with most common garden veggies, the brassica family can be problematic. Brassicas like cabbage, broccoli, kale, and Brussels sprouts grow best in lime-rich soil.
Borage prefers neutral soil and struggles in the highly alkaline conditions brassicas need. Without enough lime, borage growth becomes limited and the plant may wither.
Rather than avoiding brassicas completely, just don’t plant them right next to borage. Allow at least 12-18 inches between brassicas and borage to keep their root zones separate. With adequate spacing, both can receive their ideal soil environment.
Nightshades – Eggplant, Peppers, and Tomatoes
Like brassicas, nightshade crops like tomatoes, peppers, and eggplant also enjoy soil on the alkaline side. And as covered earlier, those high pH levels don’t suit borage.
However, nightshades only need a moderately alkaline soil, not an extremely high lime content like brassicas. With proper spacing of 12-18 inches, nightshades and borage can coexist in the same garden.
Just don’t plant borage in the same holes as your nightshades. Give them some room to spread out and modify their own root zone pH.
Mustard Greens – Another Brassica to Separate
Mustard greens are one more brassica crop that doesn’t pair well with borage. As leafy greens, mustard plants need very lime-rich soil to thrive. And they are sensitive to the lower pH levels preferred by borage.
When planting near each other, the mustard greens and borage will compete for their own ideal soil environment. To avoid this conflict, allow ample space between mustard greens and borage plantings.
In Summary
While borage makes an excellent companion for many plants, it also has a few problematic pairings:
- Potatoes – risk spreading late blight
- Fennel – emits toxins harmful to borage
- Black walnut trees – juglone residues inhibit growth
- Brassicas – need very lime-rich alkaline soil
- Nightshades – also prefer more alkaline soil
- Mustard greens – very lime-hungry like other brassicas
By avoiding these bad neighbors, you can ensure your borage reaches its full companion planting potential. With the right plant pairings, borage generously enhances the garden ecosystem. Careful companion selection allows borage to deter pests, feed pollinators, and share its nutrients without any limitations.
Borage Antagonists (do NOT plant Borage with these)
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FAQ
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