Blue Flowering Perennials: A Complete Guide To Planting, Care, And

ByRimon Chowdhury Updated on

There’s something truly magical about the color blue in a garden, isn’t there? It’s the color of calm summer skies and deep, tranquil waters. It brings a sense of peace and sophistication that few other colors can match.

But many gardeners feel that growing true blue flowers is a challenge reserved for the experts. They worry about finicky plants or colors that turn out to be more purple than blue.

I’m here to promise you that creating a tranquil blue oasis is not only possible but surprisingly simple with the right plants and knowledge. The secret lies in choosing hardy, reliable blue flowering perennials that return year after year with minimal fuss.

In this complete guide, we’ll walk through everything you need to know. We’ll explore the top-performing blue perennials, share a complete care guide with our best tips, and show you how to create a stunning, sustainable garden that will be the envy of your neighborhood. Let’s get started!

Why Choose Blue Flowering Perennials? The Undeniable Benefits

Before we dig into the “how,” let’s talk about the “why.” Beyond their sheer beauty, incorporating blue flowers into your garden offers some wonderful advantages. Understanding the benefits of blue flowering perennials will inspire you to make them a cornerstone of your landscape design.

  • A Calming & Serene Atmosphere: Blue is psychologically linked to feelings of calm and serenity. Planting drifts of blue can turn a corner of your garden into a peaceful retreat where you can unwind and de-stress.
  • Unique & Sophisticated Beauty: True blue is one of the rarest colors in the plant world. This rarity gives blue flowers an exotic and high-end feel, instantly elevating the look of your garden beds and borders.
  • A Magnet for Pollinators: Bees are particularly attracted to colors in the blue-to-violet spectrum. Planting blue perennials is a fantastic way to support local pollinator populations, making your garden an eco-friendly blue flowering perennials haven.
  • Low Maintenance & Long-Lasting: The best part about perennials? You plant them once, and they come back every year! This saves you time, money, and effort compared to planting annuals each season. They are a truly sustainable choice.
  • Incredible Design Versatility: Blue pairs beautifully with almost every other color. It can cool down hot colors like orange and red, or create a harmonious blend with pinks, purples, and whites.

Our Top 10 Must-Have Blue Flowering Perennials for Every Garden

Ready to find your perfect match? Here is our curated list of tried-and-true blue perennials that we recommend to friends and clients time and time again. This blue flowering perennials guide covers options for every type of garden.

1. Salvia ‘May Night’ (Salvia nemorosa)

If you want a workhorse plant that delivers stunning, deep indigo-blue flower spikes, look no further. ‘May Night’ Salvia is incredibly resilient, drought-tolerant once established, and blooms its heart out in late spring, often reblooming if you cut it back.

Zone: 4-8
Sun: Full Sun
Soil: Well-drained
Bloom Time: Late Spring to Early Summer

Greeny Gardener Pro Tip: After the first flush of flowers fades, shear the entire plant back by about one-third. This will encourage a second, smaller wave of blooms in late summer!

2. Perennial Geranium ‘Rozanne’ (Geranium ‘Rozanne’)

There’s a reason ‘Rozanne’ was named the Perennial Plant of the Year. This mounding plant produces an astonishing number of violet-blue flowers with white centers from late spring right up until the first frost. It’s practically foolproof.

Zone: 5-8
Sun: Full Sun to Part Shade
Soil: Average, well-drained
Bloom Time: Late Spring to Fall

Greeny Gardener Pro Tip: ‘Rozanne’ can sprawl a bit. Use it as a beautiful “filler” to weave between taller plants or as a groundcover at the front of a border.

3. Delphinium (Delphinium elatum)

For sheer drama, nothing beats the majestic spires of a Delphinium. These tall, stately plants produce densely packed flowers in shades from sky blue to deep cobalt. They are the quintessential cottage garden flower.

Zone: 3-7
Sun: Full Sun
Soil: Rich, moist, well-drained
Bloom Time: Early to Mid-Summer

Greeny Gardener Pro Tip: Delphiniums are tall and can be snapped by wind. Always stake them early in the season before they get too big. This is one of the most important blue flowering perennials tips for these beauties.

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4. Catmint (Nepeta x faassenii ‘Walker’s Low’)

Don’t let the name fool you; this plant is beloved by gardeners far more than cats! ‘Walker’s Low’ Catmint creates a cloud of hazy, lavender-blue flowers for months on end. It’s incredibly drought-tolerant and deer-resistant.

Zone: 4-8
Sun: Full Sun
Soil: Poor to average, well-drained
Bloom Time: Late Spring to Fall

Greeny Gardener Pro Tip: Like Salvia, Catmint benefits from a good haircut mid-season to keep it looking tidy and encourage a new flush of growth and flowers.

5. Siberian Iris (Iris sibirica)

Elegant and tough as nails. Siberian Iris has delicate, butterfly-like flowers in shades of blue and violet with intricate yellow and white markings. Their grassy foliage looks great all season long, even after the flowers have faded.

Zone: 3-8
Sun: Full Sun to Part Shade
Soil: Moist, average soil
Bloom Time: Late Spring

Greeny Gardener Pro Tip: Unlike Bearded Iris, Siberian Iris loves moisture and doesn’t like to dry out. It’s a great choice for areas with heavier soil or near a downspout.

6. Bellflower (Campanula)

With charming, bell-shaped flowers, Campanula comes in many forms, from low-growing groundcovers to upright bloomers. Varieties like ‘Blue Clips’ or ‘Sarastro’ offer beautiful shades of blue and are perfect for rock gardens or the front of a border.

Zone: 3-9 (varies by species)
Sun: Full Sun to Part Shade
Soil: Well-drained
Bloom Time: Early to Mid-Summer

Greeny Gardener Pro Tip: Deadhead spent flowers regularly to prevent them from setting seed. This will channel the plant’s energy into producing more blooms.

7. Baptisia (False Indigo)

A true showstopper and a fantastic choice for sustainable blue flowering perennials. Baptisia is a native North American plant that forms a large, shrub-like clump with tall spikes of lupine-like, indigo-blue flowers in spring. It’s incredibly long-lived and drought-tolerant.

Zone: 3-9
Sun: Full Sun
Soil: Average to poor, well-drained
Bloom Time: Late Spring

Greeny Gardener Pro Tip: Be patient! Baptisia takes a few years to establish its deep taproot, but once it does, it will reward you for decades. Choose its location carefully, as it does not like to be moved.

8. Veronica (Speedwell)

Veronica offers slender, graceful spikes of vibrant blue flowers that are irresistible to butterflies. Varieties like ‘Royal Candles’ are compact and well-behaved, making them perfect for adding vertical interest without taking up too much space.

Zone: 4-8
Sun: Full Sun
Soil: Average, well-drained
Bloom Time: Summer

Greeny Gardener Pro Tip: Cut back the first flower spikes after they bloom to encourage side shoots to develop and produce a second, later wave of flowers.

9. Globe Thistle (Echinops ritro)

If you want unique texture, Globe Thistle is your plant. It produces perfectly spherical, metallic-blue flower heads that look like tiny globes. They are fantastic for attracting pollinators and make excellent dried flowers.

Zone: 3-8
Sun: Full Sun
Soil: Poor, dry to medium, well-drained
Bloom Time: Mid to Late Summer

Greeny Gardener Pro Tip: The silvery-green, thistle-like foliage can be a bit prickly, so plant it away from high-traffic paths where you might brush against it.

10. Lungwort (Pulmonaria)

Here’s one for the shade garden! Lungwort is prized for its silver-spotted foliage and its charming clusters of early spring flowers that often open pink and mature to a lovely shade of blue. It’s a wonderful, low-maintenance groundcover.

Zone: 3-8
Sun: Part to Full Shade
Soil: Moist, rich in organic matter
Bloom Time: Early Spring

Greeny Gardener Pro Tip: The foliage can sometimes get a bit of powdery mildew late in the season. Simply cut off any affected leaves to keep the plant looking fresh.

Your Complete Blue Flowering Perennials Care Guide

You’ve picked your plants, now what? Don’t worry—this is the easy part! Following these blue flowering perennials best practices will ensure your garden thrives. This is our essential “how to blue flowering perennials” checklist.

Getting the Planting Right

The best time to plant perennials is in the spring or early fall. This gives them time to establish roots without the stress of summer heat. Dig a hole that is twice as wide as the plant’s container but just as deep. Gently loosen the roots at the bottom of the root ball and place the plant in the hole, ensuring the top of the root ball is level with the surrounding soil. Backfill with soil, press down gently, and water thoroughly.

Watering Wisdom

For the first year, your new perennials will need consistent moisture to establish a strong root system. After that, most of the plants on our list are quite drought-tolerant. The golden rule is to water deeply but infrequently. This encourages roots to grow deep into the soil where they can find moisture even during dry spells.

Feeding Your Blues

Perennials are not heavy feeders. Over-fertilizing can lead to lots of leafy growth but few flowers. The best approach is to amend your soil with a 2-inch layer of compost each spring. This provides a slow-release source of nutrients that will keep your plants happy all season long.

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Pruning and Deadheading for More Blooms

Deadheading, or removing spent flowers, is the single best thing you can do to encourage reblooming on plants like Salvia, Catmint, and Veronica. For mounding plants like Geranium ‘Rozanne’, a mid-summer “haircut” (shearing it back by a few inches) can rejuvenate the plant for a spectacular fall display.

Solving Common Problems with Blue Flowering Perennials

Even the toughest plants can run into issues. Here’s how to troubleshoot some common problems with blue flowering perennials so you can keep your garden looking its best.

Problem: My Blue Flowers Look Faded or Purple.

Cause & Solution: This is often a matter of sunlight or genetics. Most blue flowers develop their most intense color in full sun. In too much shade, the color can appear washed out. Also, many “blue” flowers naturally have purple undertones. Embrace the variety! For true, vibrant blue, stick with proven performers like Delphiniums or Salvia.

Problem: Powdery Mildew is Taking Over!

Cause & Solution: Powdery mildew, a white dusty coating on leaves, is common on plants like Delphiniums and Lungwort, especially in humid weather. The best defense is good air circulation. Don’t overcrowd your plants! Water at the base of the plant, not on the leaves, to keep them dry. If it appears, remove the most affected leaves.

Problem: Leggy Growth and Few Flowers.

Cause & Solution: The number one cause of leggy, floppy plants with sparse blooms is a lack of sunlight. Most of the sun-loving perennials on our list need at least 6 hours of direct sun per day to thrive. If your plant is stretching towards the light, it’s a clear sign it needs to be moved to a sunnier spot.

Frequently Asked Questions About Blue Flowering Perennials

What are the easiest blue perennials for beginners?

For gardeners just starting out, I always recommend Catmint (Nepeta ‘Walker’s Low’), Perennial Geranium ‘Rozanne’, and Salvia ‘May Night’. They are incredibly forgiving, drought-tolerant, and provide a very long season of color with minimal care.

Can I grow blue flowering perennials in the shade?

Absolutely! While many blue flowers crave sun, there are fantastic options for shadier spots. Lungwort (Pulmonaria) is a star performer for early spring color in the shade. Some varieties of Bellflower (Campanula) and Siberian Iris will also tolerate part-shade conditions beautifully.

How can I make my blue flowers look even bluer?

While you can change the color of some hydrangeas by altering soil pH, this doesn’t work for most perennials. The best way to intensify blue hues is to provide ideal growing conditions—especially the right amount of sunlight. Pairing blue flowers with complementary colors like yellow or orange can also create a visual contrast that makes the blue appear more vibrant.

When is the best time to plant blue perennials?

The ideal times for planting are spring and early fall. Planting during these cooler, often wetter, seasons reduces transplant shock and allows the plants to establish a robust root system before the stress of summer heat or winter cold sets in.

Your Journey to a Blue Garden Oasis Begins Now

Creating a garden filled with the cool, calming tones of blue is a deeply rewarding experience. It’s about more than just color; it’s about crafting a space that feels peaceful, looks sophisticated, and buzzes with the happy energy of pollinators.

By choosing the right blue flowering perennials for your space and following these simple care practices, you are setting yourself up for years of recurring beauty. There’s no need to be intimidated—you have all the knowledge you need to succeed.

So pick a favorite from our list, grab your trowel, and start painting your garden with the most serene shades on the color wheel. We can’t wait to see what you create. Happy gardening!

Rimon Chowdhury
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