Plants That Repel Blackfly

Natural deterrents for blackfly in your garden

October 16, 2025 | 10 min read
A lush garden with plants that repel blackfly

As a professional gardener based in Staffordshire, I've spent over 15 years battling various garden pests. One common nuisance is the blackfly, which can wreak havoc on your precious plants. Fortunately, there are natural ways to deter these pests by strategically planting certain species.

Quick Answer

To repel blackfly naturally, consider planting marigolds, nasturtiums, and garlic around your garden. These plants can act as effective deterrents, helping to keep your plants healthy and pest-free.

Understanding the Blackfly Problem

Blackflies are small, sap-sucking insects that can cause significant damage to your plants. They typically attack beans, nasturtiums, and other garden favourites. Here in the Midlands, they appear most actively from late spring to early summer.

Top Plants That Repel Blackfly

Marigolds

Marigolds are not just vibrant and beautiful; they also have a strong scent that repels blackfly. Plant these around the edges of your vegetable patches to create a natural barrier.

Nasturtiums

Nasturtiums work in two ways: they can deter blackfly and also serve as a sacrificial plant. Blackflies are attracted to them, sparing your other crops. These are especially handy around beans and other legumes.

Garlic

Garlic is another excellent deterrent. By planting garlic in between other crops, you create an unfriendly environment for blackfly. Plus, you get the added benefit of fresh garlic for your kitchen!

Companion Planting Techniques

Companion planting is an age-old technique that involves growing certain plants together to enhance growth and deter pests. This method is particularly effective in our UK climate, where diverse planting can naturally balance ecosystems.

Month Plant Action
March Marigolds Start seeds indoors
April Nasturtiums Direct sow outdoors
October Garlic Plant cloves

Practical Tips for Managing Blackfly

  • Regularly inspect your plants, especially during late spring and early summer.
  • Use a natural spray made from garlic and water to deter blackfly.
  • Encourage beneficial insects like ladybirds, which are natural predators of blackfly.

Conclusion

By choosing the right plants and employing companion planting techniques, you can naturally manage blackfly populations. Here in Staffordshire, and throughout the UK, these methods are both effective and environmentally friendly, providing a harmonious balance in your garden.

Frequently Asked Questions

What time of year are blackflies most active?

Blackflies are most active from late spring to early summer, depending on the climate and specific weather conditions each year.

Can I use other plants to repel blackfly?

Yes, other plants like chives and mint can also be effective, but they should be used cautiously as they can spread rapidly.

How do I make a garlic spray for blackfly?

Crush a few garlic cloves and steep them in water overnight. Strain the mixture and spray it on affected plants to deter blackfly.

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