As heatwaves become more frequent across much of the US, it's easy to assume every plant in the yard needs extra water. In reality, many established perennials, native plants, and drought-tolerant shrubs are surprisingly resilient. Others, however, can quickly become stressed during periods of extreme heat, showing signs of wilting, scorched leaves, and reduced flowering, making it important to know exactly when and where to water plants.
The key is knowing which plants are most vulnerable and stepping in before they begin to struggle. From thirsty hydrangeas in the South to sun-baked containers on patios and decks, these are the plants worth checking first during a heatwave, and how to keep them looking their best. If you're wondering which plants to water in June as temperatures climb, these are the varieties to prioritize.
Before reaching for the hose, timing matters, too. The best time to water a garden during a heatwave is early in the morning, when cooler temperatures allow moisture to soak into the soil rather than evaporating quickly. In fact, the best time to water a garden is almost always before the day heats up, giving roots time to absorb moisture and helping plants cope better with soaring temperatures. Evening watering is the next best option during prolonged periods of extreme heat, but avoid watering in the middle of the day when much of that moisture is lost before roots can absorb it.
1. Hydrangeas
Hydrangeas are often the first plants to show signs of heat stress, and it’s not unusual to see hydrangeas wilting during the hottest part of summer. Their large, soft leaves lose moisture quickly, and blooms can start to droop dramatically in peak afternoon heat, making it especially important to water hydrangeas properly during a heatwave.
I like to water deeply at the base rather than relying on quick surface sprays, as a thorough soak every few days does far more for long-term plant health than frequent, shallow watering.
In my own backyard, I also use the Eden Weighted Essential Oscillating Sprinkler from Amazon, which delivers even, consistent coverage when I need to water larger areas without constantly moving the hose.
A layer of mulch around the base is another simple step that really helps lock in moisture and keep roots cooler, especially when temperatures stay high for several days in a row.
My favorite hydrangeas are the Limelight Hydrangea and Vanilla Strawberry Hydrangea from Plant Addicts. Both have a romantic, billowy quality that makes a garden feel like a cottage fairytale. Limelight's blooms soften from lime green to blush tones, while Vanilla Strawberry's oversized flower heads gradually deepen from white to raspberry pink.
2. Container Plants
Patio pots and planters can dry out remarkably quickly in high temperatures, particularly when positioned on decks, balconies, driveways, or in south- or west-facing areas. If you have a container garden, it's worth paying particularly close attention during a heatwave, as pots tend to lose moisture far faster than plants growing in the ground.
Watering container plants may mean reaching for the hose once or even twice a day during periods of extreme heat. Check the soil regularly by inserting your finger a couple of inches into the potting mix. If it feels dry, it's time to water. Moving containers into afternoon shade can also make a noticeable difference, helping pots stay cooler and retain moisture for longer.
I've also become a big fan of self-watering solutions for summer containers. The Back to the Roots Self-Watering Terracotta Olla Pots from Amazon slowly release moisture directly to the roots, which can be a game-changer during prolonged hot spells.
I also love the look of the Square Self-Watering Planter Pot from Target, which combines a clean, modern design with a built-in reservoir that helps keep plants consistently hydrated with much less day-to-day fuss.
3. Newly Planted Trees and Shrubs
Even plant-and-forget shrubs that thrive on neglect and will eventually become drought-tolerant need extra care during their first year. Newly planted trees and shrubs haven't yet developed extensive root systems and can quickly become stressed during prolonged periods of heat.
Rather than watering little and often, give them a slow, deep soak once or twice a week. This encourages roots to grow deeper into the soil in search of moisture, helping plants establish more quickly and become far more resilient to hot, dry weather in the long term.
4. Vegetable Crops
A vegetable garden can quickly begin to struggle during extreme heat. Tomatoes, cucumbers, zucchini, peppers, and leafy greens all need consistent moisture to keep producing well, and allowing them to dry out can lead to poor harvests, stressed plants, and even blossom drop.
The best way to water a vegetable garden during a heatwave is early in the morning before temperatures climb. This gives roots time to absorb moisture before the heat of the day and minimizes water loss through evaporation. Mulching around crops will also help keep soil temperatures lower and moisture levels more consistent, allowing plants to cope much better with prolonged periods of hot weather.
If you're heading away for a summer trip, Plant Watering Stakes from Amazon are also worth considering. They slowly release water into the soil and can help keep thirsty crops hydrated while you're on vacation, giving you one less thing to worry about while you're away.
5. Hanging Baskets
Hanging baskets are among the thirstiest parts of any summer garden. Exposed to sun and moving air on all sides, they can dry out in a matter of hours during a heatwave.
To properly water hanging baskets, check them both morning and evening, watering thoroughly until it runs from the drainage holes. One of the most common hanging basket mistakes is giving plants a quick splash of water and assuming it's enough. Instead, a deep soak is essential, particularly during periods of prolonged heat.
If you're worried about keeping up with watering, the Self-Watering Hanging Planters from Amazon are a best-seller for good reason. Their built-in reservoir helps regulate moisture levels and reduces how quickly baskets dry out, making them particularly useful during heatwaves or if you're spending time away from home.
6. Roses in Full Bloom
Established roses are fairly resilient, but plants covered in flowers use significant amounts of water. During prolonged hot spells, blooms may fade more quickly and plants can begin to struggle if the soil remains dry.
To water roses correctly, give them a deep soak around the base of the plant and avoid wetting the foliage where possible. One or two thorough waterings each week is usually enough to support healthy flowering during periods of extreme heat. Deep, infrequent watering encourages roots to grow further into the soil, helping roses become more resilient during long, hot summers.
I love the Pink Double Knock Out® Roses from Plant Addicts for how reliable and floriferous they are. However, even these resilient roses appreciate a deep drink during prolonged hot spells to keep those vibrant pink blooms coming all summer long.
7. Hostas
Hostas naturally thrive in cool, moisture-retentive conditions and can quickly suffer when temperatures rise. Their broad leaves are prone to scorching and can become limp if the soil dries out, which is why hosta care becomes especially important during a heatwave.
Water deeply whenever the top few inches of soil begin to feel dry and consider providing temporary shade during the hottest afternoons. A generous layer of mulch will also help retain moisture and keep roots cooler.
One of the most popular types in the US is the Liberty Hosta from Plant Addicts, known for its bold variegated foliage and reliable performance in shaded garden spaces. It’s a great example of a variety that looks its best when given the right moisture and protection from harsh sun.
It's also worth remembering that some of the places to never plant hostas include hot, exposed spots that receive intense afternoon sun or areas with fast-draining soil. In these locations, hostas are far more likely to scorch, wilt, and struggle during prolonged periods of extreme heat.
Shop Garden Watering Essentials
One of the biggest garden watering mistakes during a heatwave is watering little and often. Frequent, shallow watering encourages roots to stay near the surface, where soil dries out fastest, leaving plants more vulnerable when temperatures spike.
Instead, water deeply and less frequently, ideally early in the morning. By prioritizing the plants that genuinely need extra moisture and encouraging deeper root growth, you’ll help your yard stay healthier, more resilient, and looking its best, even during the hottest stretches of summer.
If you want more outdoor shopping advice and the latest garden news, sign up for our newsletter and get the latest features delivered straight to your inbox.
