7 Drought-Tolerant Plants for Window Boxes — Hardy Choices That Will Survive Hot Weather

Hardy and full of vigor — drought-tolerant plants make a great choice for window boxes to add color, style and freshness into your home, without huge maintenance requirements. These tough shrubs hold many advantages and are fairly low-maintenance. You can now spruce up your windows and add character to the exterior of your home without having to worry about the heat.

But there are reasons these "dry" plants are among the best flowers for window boxes. 'Growing drought-tolerant plants in window boxes offers several benefits. These plants are low maintenance, requiring less frequent watering and care, making them popular for busy gardeners or areas with water restrictions,' Carrie Spoonemore, gardening expert and co-creator of Park Seed's From Seed to Spoon app tells us. 'Their resilience ensures that window boxes remain vibrant, providing a continuous display of color and texture'.

So, which drought tolerant plants are ideal for window boxes and all your container gardening needs? Here's what a gardening expert has to say about it.

Which window box plants won't need much water?

Why drought tolerant plants? Well, Carrie Spoonemore, gardening expert and co-creator of Park Seed's From Seed to Spoon app says: 'Choosing drought-tolerant plants contributes to water conservation, promoting sustainable and eco-friendly gardening practices. This benefits your garden and supports broader ecological efforts to manage water resources more efficiently'.

Here are 7 drought tolerant plants for window boxes — chosen by a gardening expert.

1. Marigolds

Tough, cheerful and full of life, Marigolds are at the forefront of container gardening and make the perfect drought tolerant plant for window boxes, according to Carrie.

The gardening expert says its strong-hold towards heat is due to the blooms 'deep root systems which allows them to obtain moisture from deeper soil layers. Their leaves are often thick and waxy, reducing water loss through transpiration. They can withstand dry conditions better than many other flowering plants'.

So if you're wondering how to grow marigolds, and want to spruce up your homes exterior — these bold beauties will not let you down. Depending on the variety, marigolds can grow between 6 inches to 2 feet tall.

Hardiness zone: 2-11
Soil type: Well-drained, loamy
Sunlight: Full sun

2. Verbena

Known as one of the best plants to attract butterflies, verbena is a hardy bloom that can withstand the sun in all its glory.

What makes this flower drought-tolerant? Well, Carrie tells us: 'Verbena has a robust root system that efficiently absorbs water. The foliage is often fine and sparsely arranged, minimizing water loss'. Therefore making verbena a highly drought-tolerant plant that can thrive happily in hot, sunny and dry environments.

These bright blossoms can also grow between 3-6 feet tall and make the perfect fit for window boxes.

Hardiness zone: 7-11
Soil type: Well-drained, moderately fertile
Sunlight: Full sun

Carrie Spoonemore

Carrie Spoonemore, lives in Oklahoma City with Dale and their 5 kids. She started growing food with her husband in 2015 for their family. They quickly fell in love with it and the lifestyle associated! Carrie currently makes the educational content for Park Seed’s From Seed to Spoon app and you will find her frequently in their YouTube videos demonstrating gardening techniques from their 5-acre homestead! 

3. Zinnias

For the best fast growing flower seeds, Zinnias are truly a great addition to window boxes. They're also easy to care for and drought-tolerant!

Carrie says that Zinnias 'have a relatively deep and efficient root system that helps them access water and their leaves are somewhat leathery — reducing water loss'. If you do forget to water these blooms, the expert says not to worry as 'they perform well with infrequent watering once established'.

Zinnias can grow up to 4 feet tall and their abundant height and color is known to attract beneficial garden insects such as bees and precious butterflies.

Hardiness zone: 2-11
Soil type: Well-draining, rich
Sunlight: Full sun

4. Cosmos

My personal favorite blooms, these enchanting and elegant flowers are ideal if you're looking for the best flowers that bloom in summer. They love the sun and thrive way during dry seasons.

Hardy and vigorous, gardening expert Carrie says cosmos do well in the heat as they have a deep root system which allows them to draw moisture from deep soil. 'Their fine, airy foliage also helps minimize water loss,' she adds. 'They can thrive in poor, dry soils and require minimal watering'.

It's time to learn how to grow cosmos and plant these precious flowers into your window box for a bit of color and character.

Hardiness zone: 2-11
Soil type: Well-drained, neutral soil
Sunlight: Full sun

5. Rosemary

Whether you're looking to create your own herb garden or you're wondering how to grow grocery store herbs under the sun — rosemary seems like the best place to start. It is a true burst of freshness and strength.

Carrie says rosemary is ideal if you're looking for the best drought-tolerant plant for a window box. She adds: 'Herbs like rosemary are great for growing in window boxes outside kitchens, making them perfect for cooking'.

So, how exactly is it drought-tolerant? 'Rosemary has needle-like leaves with a waxy coating that helps reduce water loss,' Carrie explains. 'Its deep root system allows it to get moisture below the soil surface'. It is also well-suited to arid conditions and can survive with minimal watering, according to the expert.

Hardiness zone: 6-9
Soil type: Well-drained, loamy
Sunlight: Direct sun

6. Lavender

If you're wondering where to plant lavender, why not start by adding it into window boxes? Its intensely attractive aroma is sure to please a guest or two and will certainly look beautiful by the windowsill — oh and best of all, they're extremely drought-tolerant.

Like most drought-tolerant plants, the Mediterranean native has an extensive root system, which helps it stay hydrated. Carries explains that its narrow, gray-green leaves covered with fine hairs also helps reduce water loss. 'Lavender thrives in hot, dry conditions and poor, well-draining soil,' she notes.

There are many different types of lavender to choose from, so if you are looking to add this ultra-fragrant herb into a container, get ready for endless freshness.

Hardiness zone: 5-9
Soil type: Well-drained, loamy
Sunlight: Direct sun

7. Oregano

As well as being the perfect kitchen plant for your cooking space, oregano can also thrive in window boxes due to its drought-tolerant properties.

This is due to its small, thick leaves that 'that conserve water and a robust root system that can extract moisture from deeper soil layers,' according to Carrie. It can outstand dry, rocky soils and requires minimal watering — making it the best possible choice for those low maintenance garden ideas.

Hardiness zone: 5-11
Soil type: Well-drained, sandy
Sunlight: Full sun

Care tips for drought-tolerant plants in window boxes

In order to get the best out of your drought tolerant plants in window boxes, there are a few steps you can take to help ease your container gardening journey. Here are a few tips and tricks you can follow — according to gardening expert Carrie Spoonemore.

'Starting with the right soil is crucial,' says Carrie. 'Using a high-quality potting mix designed specifically for containers ensures good drainage, which prevents waterlogging—a common issue that can harm drought-tolerant plants'. The expert says it is also essential that your window boxes have enough drainage holes to allow excess water to escape.

Although they are fairly low maintenance, Carrie says 'effective watering practices are vital for maintaining drought-tolerant plants'. During the establishment period, newly planted seeds or young plants require regular watering until their roots are well-developed. Once the plants are established, you can water them less frequently'.

Another care tip from Carrie is applying the right amount of fertilizer. She tells us: 'Applying a balanced, slow-release fertilizer sparingly during the growing season can support their growth'.

Last but not least, pruning and deadheading regularly also encourage new growth and prolongs blooming.

'Even though drought-tolerant plants are resilient, monitoring them for pests and taking action if any are detected to prevent infestations is essential,' Carrie adds.