For some gardeners, ferns are a delightful addition to the landscape, providing lush greenery and a touch of prehistoric charm.
For others, particularly when ferns grow where they aren’t wanted, they can be a recurring nuisance. If you belong to the latter group and are trying to prevent ferns from growing back in certain areas, this guide is for you.
Understanding Fern Growth
Basic Biology of Ferns
Unlike most plants we’re familiar with, ferns don’t produce flowers or seeds. Instead, they’ve been reproducing via spores for over 360 million years. This ancient group of plants has a unique life cycle and biology that has allowed them to colonize habitats from tropical rainforests to arid deserts.
Fern Lifecycle: A Dual Phase
Ferns have a two-phase life cycle, also known as alternation of generations:
- Sporophyte Stage: This is the stage most people are familiar with. The sporophyte is the typical fern plant with fronds. On the underside of some fronds, there are often small, usually brown, spots called sori. These sori produce spores.
- Gametophyte Stage: When the tiny spores land in a suitable spot, they grow into a small, heart-shaped plant called a prothallus, representing the gametophyte stage. This phase of the lifecycle is inconspicuous and thus often overlooked. The prothallus produces both male and female gametes. When the male gamete fertilizes the female gamete, a new sporophyte fern plant begins to grow, completing the cycle.
Rhizomes and Roots
Central to understanding fern growth is the rhizome:
- Function: Rhizomes are horizontal stems that grow either at the soil surface or underground. They store energy for the fern and serve as the plant’s main growing structure.
- Types: Some rhizomes are short and produce a crown of fronds, as seen in many garden ferns. Others are long and creeping, enabling the fern to spread and colonize new areas.
Spore dispersal is vital for fern propagation:
- Wind Dispersal: Most ferns rely on the wind to disperse their spores. The lightweight and tiny nature of the spores makes them ideal for traveling long distances.
- Environment: For a spore to grow into a gametophyte, it requires a moist environment. This is why you’ll often find ferns in damp, shady locations.
Ferns are incredibly adaptive:
- Light: While many ferns thrive in the dappled shade of woodlands, some varieties have adapted to brighter or even direct sunlight.
- Soil: Ferns can be found in a variety of soil types. Some prefer the rich, moist soils of a forest floor, while others can be found on rocky outcroppings or in sandy soils.
- Water: Water is crucial for fern reproduction, particularly for the gametophyte stage. However, different fern species have varying water needs. While many associate ferns with damp environments, there are also desert-adapted ferns that have evolved to cope with arid conditions.
Methods to Prevent Fern Regrowth
Controlling fern growth requires a combination of persistence and the right approach. Here are more detailed methods and suggestions:
1. Physical Removal
- Deep Digging: To ensure you get most of the rhizomes, dig deep around the base of the fern. Using a fork can be more effective than a spade as it lessens the chance of cutting rhizomes, which could lead to further propagation.
- Regular Checks: After removal, check the area frequently for signs of regrowth and promptly remove any new shoots.
- Mowing or Trimming:
- Consistency: To weaken the ferns, it’s essential to mow or trim regularly. This starves the plant of the energy it would otherwise store in its rhizomes.
- Complement with Other Methods: Mowing should be part of a broader strategy, ideally combined with methods like mulching.
2. Limiting Light
- Tree and Shrub Management:
- Pruning: Trim overhead branches from trees and large shrubs to allow more sunlight into the area.
- Strategic Planting: If landscaping or re-planting, position larger plants in a way that they don’t create extensive shaded areas favorable to ferns.
3. Natural Suppressants
- Material Choices: Opt for coarse mulches like wood chips or bark. These are less penetrable and can effectively suppress fern growth.
- Depth: Aim for at least a 4-inch layer of mulch for optimal suppression.
- Boiling Water:
- Precision: Be cautious and precise when pouring to target only the ferns and not surrounding vegetation.
- Frequency: This method might require multiple applications for effectiveness.
4. Chemical Control
- Spot Treatment: Instead of widespread spraying, use a sponge or brush to apply the herbicide directly to the fern, minimizing collateral damage.
- Repeated Application: Depending on the hardiness of the fern and the effectiveness of the herbicide, several applications may be necessary.
- Eco-friendly Options: Consider herbicides that have a lower environmental impact or are labeled as biodegradable.
- Natural Alternatives:
- Vinegar: A strong vinegar solution can be an alternative to chemical herbicides. However, like other methods, it can affect nearby plants, so apply with care.
5. Biological Control
- Fern-specific Pests:
- Research: Before introducing any pests, understand their lifecycle, potential impact on the local ecosystem, and whether they might become a problem themselves.
- Consult Experts: If considering this method, consulting with a local horticulturist or ecologist is advisable.
6. Soil Alteration
- Change pH Levels: Some ferns prefer either acidic or alkaline soils. By adjusting the soil’s pH (using lime for increasing alkalinity or sulfur for increasing acidity), you can make the environment less hospitable for ferns. Do note that this can impact other plants, so ensure you’re making changes that align with the needs of the plants you wish to keep.
While ferns are undoubtedly beautiful and beneficial in many settings, there may be times when their presence is unwelcome.
Whether you choose physical removal, natural suppressants, or chemical treatments, the key to keeping ferns from growing back is persistence and a multi-faceted approach. By understanding how ferns grow and spread, you’ll be better equipped to keep them in check.
Also, you may like some more gardening articles:
- What to Plant with Ferns [Complementing the Green Fronds]
- What is the Best Fertilizer For Ferns?
- Why Do Hanging Plants Lose All Their Flowers?
- Why Are Staghorn Ferns So Expensive?
- How Often Should You Water Ferns?
- When to Bring Ferns inside?
- Why Are My Ferns Turning Brown? [Reasons & Preventions]
FAQs on Fern Control
Are ferns invasive?
While some fern species can be aggressive spreaders, not all are invasive. It depends on the variety and the local ecosystem.
Will mowing ferns kill them?
Regular mowing can weaken ferns and may eventually kill them, but it’s more effective when combined with other control methods.
Is it harmful to other plants if I use herbicides on ferns?
Yes, if not applied carefully. Always read and follow the herbicide’s label, and consider spot treatments to target ferns while sparing other plants.
Can I transplant unwanted ferns instead of killing them?
Absolutely! Ferns can be dug up and relocated to a more suitable location if you or someone else wants them.
Why are ferns so resilient?
Ferns have been around for millions of years and have evolved numerous strategies for survival, including spreading via rhizomes and spores, making them particularly tenacious.
I’m Elsa, and I love gardening. I started GardeningElsa.com as a resource for other gardeners, and I offer expert advice on gardening topics such as plants, flowers, herbs, and vegetable gardening. On my website, I share my latest tips and tricks for creating beautiful gardens. When I’m not working on my website, you can find me in my own garden, tending to my plants and flowers. Read more about me.