8 Outdoor Plants with Blue and Cool Toned Leaves

There are plenty of striking blue flowers in the plant and horticultural world. From periwinkle blue hydrangeas to azure delphiniums. Like plants with pink leaves, the blue coloring in these flowers is caused by anthocyanins. 

Blue petals are gorgeous, but what about blue foliage… are there plants with blue leaves?

Are there plants with true blue leaves?

Blue isn’t a color that many would generally associate with plant leaves — of this world anyway! Pandora and other alien worlds maybe… but back here on Earth, there’s actually a scientific reason why most things in nature are not blue!

To get into the science of why, chlorophyll likes to absorb red and blue light from sunlight. So if a plant leaf was blue, the blue light waves would instead be reflected away — which is counterproductive for plant leaves! Plants need to absorb as much light as possible for photosynthesis, to keep them healthy. This makes blue the rarest plant color.

Why do some leaves look blue?

Some plants, however, can have striking, cool, blue-green colored leaves. Blue leaves aren’t technically blue. They simply have a leaf structure that helps to reflect blue light that allows us to see them as blue.

Their cool tones pair exceptionally well with plants with white and purple flowers or foliage. But they also create breathtaking contrast when paired with bright green foliage too. Like the golden hue of the bright, lime green foliage of creeping Jenny or dwarf cypress conifers.

Best outdoor garden plants with blue leaves

While the foliage on these plants may not be vivid shades of sapphire or sky blue, they do have delightful dusky tones that can bring a cooling contrast to your garden space.

1. Hosta

For dramatic foliage and cool blue tones, I wholly recommend checking out the hostas in your local nursery.  

My personal favorite hosta is ‘Blue Mouse ears’, which is a sweet little variety with small, velvety-looking leaves in a delightful shade of dusky blue.

They’re a very popular group of plants and for good reason! Shade-tolerant, moisture-loving, and beautiful flowers too. So there’s a great selection to choose from, even different shades of dusky blue.

Other blue hosta cultivars include:

• Hosta ‘Yankee Blue’
• Hosta ‘Canadien Blue’
• Hosta ‘Elegans’
• Hosta ‘Diamond Lake’
• Hosta ‘Prairie Sky’

To create a mix of textures, pair the broad leaves of your blue hosta with the pink feathery flowers of Rodgersia (another shade loving plant).

2. Dwarf Blue Spruce (Picea)

Blue spruce is a well-known conifer with silvery blue needles, but in a small garden space, a smaller specimen is definitely required.

Enter dwarf conifers! I’m a huge fan of dwarf conifers, in part because of their small size and evergreen foliage, but also their varied color ranges.

Some lovely dwarf blue spruces include:

• Picea sitchensis ‘Papoose’
• Picea pungens ‘Edith’
• Picea pungens ‘Glauca Globosa’ (dwarf globe blue spruce)

If space isn’t too much of an issue, then a slow-growing Picea ‘Fat Albert’ (3.5m maximum height) would be a very striking option.

3. Stonecrop (Sedum)

Stonecrops come in all shapes, sizes, and colors — including blue! As succulents, the fleshy leaves of blue stonecrops have more of a pastel blue shade. But they still bring a lovely cooling tone to container rock gardens or borders.

Some of the loveliest blue stonecrops include:

• Sedum ‘Blue Cushion’
• Sedum ‘Blue Spruce’
• Sedum ‘Blue Elf’
• Sedum ‘Cape Blanco’

Sedum ‘Blue Pearl’ also has a very striking blue color. Its succulent leaves are technically purple, but the epicuticular wax coating gives it a midnight blue color.

4. Euphorbia ‘Glacier Blue’

Evergreen and hardy, you can enjoy the cool, blue-green tones of Euphorbia ‘Glacier Blue’ year-round.

It will produce subtle green flowers in summer, but it’s the striking, variegated blue foliage that steals the show. Perfect for adding a dense cluster of cool-toned foliage into borders.

5. Festuca glauca 

Delicate, feathery, and blue, Festuca glauca is a grass that can bring textures and unusual color to your garden space.

In summer, you’ll also be treated to a haze of tall stems with golden feathered flowers. It really brings a lovely ethereal look to borders or containers.

Like Euphorbia, it’s incredibly drought-tolerant, making it a perfect plant for a low maintenance garden.

6. Dwarf Juniper

Like dwarf blue spruce, dwarf juniper is a great way of bringing color into your space. Because of their small size and evergreen foliage, dwarf conifers really do make excellent specimen plants.

Dwarf junipers with cool, blue foliage include:

• Juniperus ‘Blue Star’
• Juniperus horizontalis ‘Blue Chip’
• Juniperus horizontalis ‘Icee Blue’
• Juniperus scopulorum ‘Moonglow’

7. Hebe ‘Quicksilver’

Hebes make excellent standalone shrubs and they come in such an amazing array of colors and variegated patterns. There are some hebe plants with pink leaves and others with striking cream and green variegation.

But hebe ‘Quicksilver’ has unique blue-green leaves. In summer it produces a flush of delicate purple flowers which compliment its cool foliage perfectly.

8. Eucalyptus

With a silvery, blueish tint, Eucalyptus (Eucalyptus gunii) is a plant that will bring a more subtle blue hue to your space. Because of its upright growth, it’s a great evergreen plant for a balcony garden.

The oils found in Eucalyptus leaves are actually responsible for the blue haze that hangs over the well-named Blue Mountains in Australia!

For more neutral, silvery tones, Eucalyptus ‘Azura’ is a good option. But for a deeper blue-green hue Eucalyptus ‘Baby Blue’ is perfect.

If you’re looking for more dramatically colored foliage, check out my lists of other unusually colored plant leaves! From bright pink hebe shrubs to black-leaved hydrangeas.

• Plants with black leaves
• Plants with purple leaves
• Plants with pink leaves
• Plants with silver leaves
• Plants with orange leaves
• Plants with red leaves