How to Revive a Garden After a Heatwave

Heatwaves and extremely hot spells can wreak havoc on our gardens, leaving behind faded flowers, crispy leaves, drooping stems and brown lawns.

But whilst it’s tempting to remove everything that looks past its best, hold your horses. The damage to your plants could be superficial, many will recover once temperatures fall and conditions become more manageable.

If your garden is looking a little sorry for itself this summer, here's some useful tips from our resident flower expert David Denyer on how to bring it back to life and encourage healthy new growth.

Sunset

Do I need to cut everything back after a heatwave?

Resist the temptation to start hacking away at every unsightly thing. Whilst scorched, brown or wilted foliage can look unsightly, it can also provide some protection for the plant while it recovers. At this point the plant is already weakened and removing additional foliage will place it under additional stress.

You’ll likely find that your garden will respond positively when normal temperatures arrive, so hold out until then. Look for new shoots, green stems or healthy buds before deciding what needs to go.

There is a simple test that can help determine what might need to go too. Gently scratch the surface of a woody stem with your fingernail. If there is green underneath, there is a good chance the stem is still alive. If it is completely brown and brittle, it may be worth pruning it back to healthy growth.

Once plants have had time to recover, remove dead or badly damaged material with clean, sharp secateurs.

Should I feed plants after a heatwave?

Much the same as our advice around cutting back, it’s all about patience when it comes to feeding too as this isn't necessarily the first thing your garden needs after extreme heat.

When plants are under stress like that produced by a heatwave, they are focused on survival and recovery, rather than producing lots of vigorous new growth. Therefore, if you apply fertiliser too soon you can potentially encourage growth before the plant is ready to support it.

Concentrate your efforts instead, on getting the soil back into good condition. Once plants are showing signs of recovery and producing fresh growth, then you can reach for a suitable general-purpose feed.

Check your soil

Soil that is compacted and difficult for water to penetrate is another unwanted result of extremely hot weather conditions and heatwaves.

Wait for the first rainfall to check whether water is actually soaking into the soil. If you find it’s simply running off the surface, try to loosen the very top layer around plants with a hand fork, taking care not to damage shallow roots.

You can also try adding organic matter like well-rotted garden compost as this can improve soil structure and its ability to hold moisture. 

By adding organic matter to the soil you’ll increase water retention and its availability to plants, making the garden more resilient during future dry spells.

Sprout in soil

Caring for potted plants after a heatwave

Heatwaves and extremely hot weather don’t just affect plants in the ground, but potted plants also. Containers have a limited amount of soil, which means they are at risk of drying out considerably faster than plants growing in the ground.

It isn’t a one size fits all approach here, make sure to check each pot individually rather than assuming every plant needs the same treatment. Where you find that compost has become extremely dry and has pulled away from the sides of the container, water slowly so that moisture has time to penetrate rather than running straight through the pot.

Once the plant has started to recover, remove dead flowers and foliage and check that drainage holes haven't become blocked.

The beauty of potted plants is that you can move them around if they are struggling. A plant that struggled badly in a south facing spot may fare much better somewhere with morning sunshine and afternoon shade. So try moving those around that look to be in particularly bad shape, giving them a spot with more shelter and shade.

Does extreme heat kill your lawn?

A brown lawn is not always a dead lawn.

Grass tends to enter into a dormant state during periods of drought, turning yellow or brown while conserving energy. It will green up again once temperatures and rainfall return. In fact, lawns can be left to recover naturally rather than being heavily irrigated during dry periods.

When the grass is brown, avoid cutting it extremely short, instead wait until you see fresh green growth returning before gradually resuming normal mowing.

There may be bare patches that need reseeding, but again, wait until conditions return to normal before doing so as seeds need sufficient moisture to establish.

Browning lawn

Deadhead flowers to encourage a second flush

Some flowers may survive the heatwave but just look a little tired, this is where deadheading can make a huge difference.

With plants such as roses, geraniums, dahlias and many bedding plants you can remove the dead blooms. This will prevent the plant from putting unnecessary energy into producing seed and encourages it to concentrate on new growth and flowers instead.

Avoid deadheading everything as some plants produce attractive seed heads that provide food for birds or add winter interest, while others naturally flower only once.

Look out for pests and disease

The stress that a heatwave can cause plants can open them up to secondary problems like being susceptible to pests and diseases.

Inspect the undersides of leaves and new shoots for aphids, spider mites and other pests, as well as looking for unusual spotting and mould.

It might be the case that not every brown leaf is the result of the heat. If plants don’t show signs of recovery after normal temperatures have resumed and plants have been watered appropriately, investigate whether something more sinister might be at play.

Remove any badly affected leaves to improve airflow and help prevent problems from spreading.

Learn from what survived

Heatwaves are a common occurrence in the UK now, so to avoid starting your investigations from scratch every year, take notes.

Note which plants barely seemed to notice the heat? Which ones wilted within days? Were some areas of the garden noticeably more resilient than others?

This will help you make better planting decisions next time round, paying particular attention to choosing plants that are naturally better suited to hot and dry weather and considering using soil that can deal with extreme heat and drought conditions too.

You won’t have to completely change your garden. But it’s good to know that you can replace plants that consistently struggle, with varieties better suited to heatwave conditions. Mediterranean-style plants and those with silver or grey-green foliage can be particularly useful in sunny, dry areas.

Equally, a plant that struggled may simply have been planted in the wrong location. Moving it to a position with a little more shade could make all the difference.

Give your garden time

The most important thing to remember with all of this advice is to give it time and don’t overreact immediately.

It’s all about careful monitoring, some plants will recover within days once temperatures drop, while others may take several weeks to produce fresh growth.

Remove genuinely dead growth when appropriate and resist the temptation to interfere too much.

Yes a heatwave will leave your garden looking tired, but it doesn't necessarily mean the damage is permanent. Show some patience and some targeted TLC and you’ll find many plants will recover and produce fresh growth before the season is over.

And when the next hot spell arrives, the plants that made it through this one can provide a useful guide to creating a garden that's better equipped for whatever the British weather throws at it next.

Green garden

Author

David Denyer

Euroflorist's Flower Expert

With over 35 years of floristry experience, David Denyer is a renowned master in his field. His talent and artistic vision have earned him numerous accolades and awards, establishing him as one of the industry's leading figures. David has captivated audiences worldwide, showcasing his passion for floristry in Europe, China, Australia, and America. His captivating demonstrations have left a lasting impression on floral enthusiasts globally. In 2023, David made a memorable appearance on the prestigious television show, Gardeners World, further solidifying his reputation as an exceptional florist. David's journey to success began in 1996 when he was named Interflora "Florist of the Year." Since then, he has represented the United Kingdom in the "Europa Cup" and achieved consecutive Chelsea Gold Medals and Best in Show titles at the renowned Chelsea Flower Show from 2000 to 2003. In July 2004, David was once again named Interflora "Florist of the Year" and led his team to victory at the Interflora World Cup in Melbourne, Australia. He continued to impress with another Chelsea Gold Medal in 2005 and received a Gold Medal in 2011 for his floral installation titled "A Sense of Perspective." David's Accolades: July 1996: Interflora "Florist of the Year"; September 1999: Represented the UK in the "Europa Cup" in Austria; May 2000-2005: 6x Consecutive Chelsea Gold Medal and Best in Show - Professional Floristry; July 2004: Interflora "Florist of the Year"; September 2004: Interflora World Cup Winners in Melbourne, Australia; 2011: Chelsea Gold Medal for "A Sense of Perspective" floral installation; 2023: Appeared on Gardeners World in 2023; David's vast experience and expertise now benefits Eflorist customers. Understanding the emotional power of flowers, he ensures that every customer receives the utmost delight when enjoying their thoughtfully sent bouquet.