Have Your Plants and Shrubs Survived the Heat?

The summer of 2026 has been brutal for gardens across Europe. Europe is the fastest-warming continent, with temperatures rising by approximately 0.56°C per decade since the mid-1990s, more than double the global average. For homeowners who have spent months nurturing their borders, the sight of brown, crispy, or collapsing shrubs after a heatwave is a gut punch. The good news is that plants are far more resilient than they look. Many are dormant, not dead, and with the right approach, you can rescue most of them. This guide walks you through how to assess damage, prioritise your recovery effort, and get your garden back on its feet.

Key Takeaways

• Wilting alone means very little: When temperatures are exceptionally high and prolonged, plants can lose water through evaporation much faster than the roots can absorb it, and wilted, drooping leaves are often the first signs of heat stress, not death. Always assess before you act.

• The scratch test is your most reliable tool: A simple and effective way to test plant vitality is the scratch test, using a fingernail or pocketknife, gently scratch away a small section of bark on a twig or stem. If the tissue beneath is green and moist, that part of the plant is still alive. Do this before removing any plant.

• Do not prune or fertilise during or right after a heatwave: Fertiliser is not going to repair any damage, and fertiliser tries to encourage new growth. With a heat-stressed plant, you do not want to encourage growth; you want to encourage healing, so during a heatwave is not the best time to fertilise your plants.

• Heatwaves are becoming more frequent: Research shows that in the five decades between 1950 and 1999, Europe endured five intense heatwaves. Between 2000 and 2021, there were 18 such heatwaves. Prepare your garden for the long term, not just this season.

Quick-Start Prioritisation Framework

Start here if you are:

• A first-time gardener: Run the scratch test on every woody plant before doing anything else. This single step prevents you from removing plants that are still alive.

• Short on time: Focus water exclusively on new plantings and container plants first, these lose their root moisture fastest.

• Managing a large garden: Group your plants by urgency using the table above, and work through them in that order over several mornings.

How to Tell Whether Your Plants Are Dead or Dormant

This is the question every gardener is asking right now, and the answer is nearly always "wait and check" rather than "dig it up."

The Scratch Test

The easiest way to determine if your tree or shrub is still alive is to perform a scratch test. It involves gently removing a small part of the outer bark to see if the inner bark is a shade of green, use a fingernail or a garden knife to scrape a very thin outer layer away. According to Wilson Bros Gardens' scratch test guide, if the underbark is brown, black, or grey, that section is dying or dead, but keep working down toward the base, because even if only the trunk shows green, the roots may still be viable.

Pro tip: Always test at least two or three spots along a stem before writing it off. Test several areas, working your way down the stem toward the roots, plants can have dead upper growth but still be alive at the base.

The Bend Test

Another quick check is the snap test. Bend a small twig to see if it's still flexible, live wood will bend, while dead wood will snap cleanly and feel brittle. Use both tests together for a reliable result.

Signs That Your Shrubs Are Struggling, But Alive

By the time visible decline appears, the stress may already be affecting the canopy, root system, or overall vigour. Common signs of heat stress in trees include thinning canopies, smaller-than-normal leaves, early leaf drop, browning leaf margins, and dead twigs at the ends of branches. These are warning signs, not death sentences. Most plants will return to typical production after a heat wave is over.

The Right Way to Water After a Heatwave

Pouring large amounts of water onto a heat-stressed plant is a common mistake. In my experience, it is the most frequent error I see gardeners make after a hot spell, and it can cause more harm than good.

Water Deeply, Not Constantly

Water deeply and efficiently. Use drip irrigation or soaker hoses to minimise evaporation. Overhead sprinklers lose water to the air before it reaches the roots. Water early in the morning so plants can take up moisture during the day and excess water evaporates by evening. This advice from OSU Extension Service applies whether you are in the middle of a heatwave or recovering from one.

Check the Soil First

Not every plant needs extra water during a heatwave. Established shrubs, mature perennials, and drought-tolerant plants often cope perfectly well with little additional watering. Instead of watering automatically, check the soil first. If it's still damp a few centimetres below the surface, your plants can probably wait another day. Overwatering can weaken roots and even increase the risk of disease.

Special Care for New Plantings

Pay close attention to recently planted plants. Perennials, trees, and shrubs planted earlier in the year have not yet rooted in fully. With most roots still in the original root ball, that root ball can quickly dry out. Check newly planted plants frequently and water both the original root ball and the surrounding soil if either is dry. According to Iowa State University Extension, the same priority applies to anything planted within the last three years.

Pro tip: For potted plants that have completely dried out, Dan Cooper Garden recommends submerging the entire pot in a bucket or sink of water until fully soaked. Sometimes, dry compost pulls away from the pot's sides, so water just runs through without soaking in, the best way to rehydrate them is to put the whole pot in a bucket or sink of water until it's fully soaked.

What to Do (and What to Leave Alone) After the Heat Breaks

Hold Off on Pruning

Shrubs are usually best left until spring before cutting back any damaged growth. As new growth emerges, it's easier to establish whether branches and stems are dead or just dormant, so avoid cutting them back too soon. It can be tempting to remove brown or damaged-looking branches straight away, but waiting gives the plant the best chance to recover. This advice from Ideal Home is particularly important for spring-blooming shrubs, pruning too soon can encourage tender new growth that may be vulnerable to future heat, and if you cut back spring-blooming shrubs like rhododendrons, you may also remove buds that would bloom next year.

Mulch the Soil

Once temperatures drop, applying mulch is one of the highest-impact actions you can take. A 2-3 inch layer of mulch around trees, shrubs, and garden beds is one of the cheapest, highest-impact things you can do. Organic mulches like wood chips, straw, or shredded bark work best and break down over time to improve soil health. According to Dennis' 7 Dees landscaping, keep mulch away from the base of the plant itself to prevent rotting.

Watch for Pests

Watch out for pests. Just like weeds, pests can take advantage of the conditions after a heatwave. Damaged or weak plants are easy targets for slugs, snails, aphids, and red spider mites. I've found that a weekly check of the undersides of leaves during the recovery period catches problems early, before they become serious. Stressed trees are more likely to attract damaging insects like wood-boring beetles, so keep a close eye on bark condition too.

Building a More Heat-Resilient Garden for Next Summer

In my experience, a garden that weathers a heatwave well is one that was prepared well before the temperatures peaked. The gardens that stay beautiful after a heatwave are not necessarily watered the most; they are simply prepared the best.

Healthy soil acts like a sponge. Ground that's rich in organic matter holds far more moisture than poor, compacted soil, meaning plants continue receiving water long after rainfall has stopped. Adding homemade compost or well-rotted manure each year gradually improves the soil's ability to cope with dry conditions.

At Holland Kertészet, you can find a range of drought-tolerant shrubs and perennials that are well-suited to the warming summers of Central Europe, a practical way to future-proof your borders without starting from scratch.

If heatwaves are becoming a regular part of your climate, consider gradually shifting toward drought-tolerant and native plants. They're adapted to local conditions, need less water once established, and hold up far better under extreme heat, saving you time, money, and stress the next time a heatwave hits.

Frequently Asked Questions

How do I know if a shrub is dead or just dormant after a heatwave?

The scratch test is the most reliable method. Using a fingernail or pocketknife gently scratch away a small section of bark on a twig or stem. If the tissue beneath is green and moist, that part of the plant is still alive. If it's dry and brown, that section may be dead. Test multiple points along the stem and work your way down toward the base before giving up on a plant.

Should I cut off all the brown and scorched leaves after a heatwave?

Hold off on pruning. It's fine to remove dead flowers, but avoid cutting off partially scorched leaves or doing any hard pruning. Damaged leaves can still provide shade for healthy foliage, and those with green tissue can continue photosynthesising. Wait until you see new growth emerging before cutting anything back significantly.

How long does it take for heat-stressed plants to recover?

Recovery time varies by plant type. Most annuals show perked foliage and fresh buds within a week, while herbaceous perennials take roughly 1-2 weeks to push clean new growth. Woody shrubs need longer to set replacement shoots, often 2-3 weeks. If no improvement appears after two weeks, reassess whether the plant is viable.

Is it safe to fertilise my plants immediately after a heatwave?

During periods of intense heat inducing new growth is not ideal. Wait until a cooler period to fertilise. Fertilising too early pushes the plant to produce tender new shoots that are vulnerable to any remaining heat stress, and it can burn already-weakened roots. Wait for clear signs of recovery first.

Sources

1. Heat Wave in the Garden: How to Identify and Prevent Heat Stress in Plants, OSU Extension Service. Comprehensive guide on heat stress identification and prevention. https://extension.oregonstate.edu/catalog/em-9556-heat-wave-garden-how-identify-prevent-heat-stress-plants

2. How to Care for Plants After a Heat Wave, OSU Extension Service. Post-heatwave recovery advice from horticultural specialists. https://extension.oregonstate.edu/news/how-care-plants-after-heat-wave

3. Managing the Garden in Extreme Heat, Iowa State University Extension. Practical guidance on plant physiology during extreme heat. https://yardandgarden.extension.iastate.edu/how-to/managing-garden-extreme-heat

4. How to Perform a Scratch Test, Wilson Bros Gardens. Step-by-step guide to testing woody plant viability. https://www.wilsonbrosgardens.com/scratch-test.html

5. Five Things to Know About Heat Waves in Europe, Phys.org. Data on European heatwave frequency and trends. Copernicus Climate Change Service (C3S). Data on European heatwave frequency and trends. Copernicus Climate Change Service

6. What Do We Know About Europe's Early and Intense Heatwave in May 2026, Copernicus Climate Change Service. Data on European warming rates. https://climate.copernicus.eu/what-do-we-know-about-europes-early-and-intense-heatwave-may-2026