What exactly is a false fall? How gardeners can help get plants and trees through this tricky time

You may have noticed some of the classic signs of fall in your garden in recent weeks, with leaves browning and dropping from trees, shrubs and hedges taking on a redder or orange tinge, and fall berries ripening.

It may conjure images of cosy fall nights, a seasonal wardrobe change, and pumpkin spiced lattes, but the temperatures can revert quickly to summer levels. This is because many of us are experiencing a phenomenon known as a 'false fall', which may be a temporary shift before the final weeks of warmth.

Just like a false spring, where there is a period of unusually warm weather before the temperatures drop again to wintery levels, such fluctuations due to a false fall can confuse gardeners and pose problems for plants. So, exactly what is a false fall, and are there any steps we can take to help the plants in our yard?

What is a false fall?

A false fall is a period of cooler temperatures that occurs in late August or early September, but this can be followed by a few more weeks of summer before the weather truly settles into the expected norm for fall.

The stress from extreme summer temperatures causes trees and plants to display the tell-tale signs of seasonal change when the temperatures fall, even if for a short period. Plants notice the shift in temperatures and adapt accordingly, plus any leaf drop can be accelerated if the plants are suffering from a lack of moisture.

As climate change makes extreme heat more commonplace, a false fall is becoming more frequent. Premature leaf drop may indicate that trees are stressed, which can worsen if temperatures return to summer levels for a few weeks before settling into normal fall conditions.

The signs of a false fall you'll definitely notice

It may be welcomed and look attractive, but a false fall is an illusion, as it appears like a true fall has occurred. The temperatures will feel cooler and crisper, and it can feel like a nice break from the warmer days of summer.

The trees in your yard will start changing color, showing those glorious fall hues of red, yellow, or bronze, and there may be fallen leaves strewn on your lawns and borders. Along with trees, your garden hedges may also begin showing those fall signs, such as color changes and berry ripening.

While these colorful fall shades may look stunning as a backdrop to fall-flowering perennials in beds or fall-blooming native plants in containers, they may indicate stressed plants that can struggle if temperatures increase again after the onset of this false fall.

What can gardeners do to help plants during a false fall?

A false fall, followed by a few final weeks of summer-like temperatures, will further stress trees and plants already struggling after intense periods of heat and drought. But there are a couple of measures gardeners can add to their early fall gardening checklist to help:

Watering plants deeply during periods of drought and warmth ensures that moisture reaches the roots, where the plants need it most.

At the end of a dry summer, soil can become compacted, and any rainfall may struggle to penetrate. Watering deeply and using drip irrigation or soaker hoses helps the water penetrate deeper into the soil and reach the root zone.

Mulching plants in early fall will also lock moisture into the soil, making it available to plants for a longer period rather than being lost to evaporation in warmer temperatures.

There are many plants to mulch in September, including trees, shrubs, and perennials, and the best types of mulch to use include compost and bark. On top of locking moisture into the soil, it also reduces stress by protecting roots from winter weather.

It may be tempting to fertilize trees or shrubs in early fall if they look stressed. However, this would be a fertilizing mistake.

It won’t simply give plants energy to recover before winter, but also encourage a new flush of late growth that will be damaged by the winter colds, leaving the plant more susceptible to pests and diseases.

To prepare for fall, check long-range weather predictions to see if you should expect any extreme cold during the season. This allows you to get ahead of any early snow, heavy rainfall, or hard frosts.

For example, the Farmer's Almanac Fall Forecast 2025 warns of thunderstorms, along with early snow in October for some regions. You want to be proactive and prepared to protect plants from frost if you live in affected areas.