Purple Flowering Tall Plants: 10 Stunning Choices For Vertical Impact

ByRimon Chowdhury Updated on

Is your garden feeling a little… flat? You’ve got the groundwork laid, but it’s missing that ‘wow’ factor, that vertical element that draws the eye upward and creates a sense of depth and magic.

I know the feeling well. It’s a common hurdle for so many gardeners! But I’m here to let you in on a secret that professional designers use all the time: adding statuesque, vibrant blooms. And in this guide, we’re going to focus on the most regal and enchanting color of them all.

I promise that by the end of this article, you’ll feel completely confident in choosing, planting, and caring for the perfect plants to add that missing dimension. We’ll explore the absolute best purple flowering tall plants, dive into a complete care guide to help them thrive, and even troubleshoot a few common problems. Get ready to transform your garden from flat to fabulous!

Why Choose Purple? The Surprising Benefits of Purple Flowering Tall Plants

Before we dig into our top picks, let’s talk about why this combination is so powerful. Adding height to your garden is like adding architecture—it creates structure, defines spaces, and provides a backdrop for smaller plants. The benefits of purple flowering tall plants go beyond just looking pretty.

In garden design, purple is a wonderfully versatile color. It can be cool and calming, pairing beautifully with blues and whites for a serene feel. Or, it can be rich and dramatic, creating a striking contrast with yellows and oranges. It’s a color that exudes both sophistication and a touch of wild magic.

From an ecological standpoint, many of these plants are a magnet for pollinators. Bees, butterflies, and hummingbirds are often drawn to purple hues. By incorporating these blooms, you’re not just creating a beautiful space for yourself; you’re building a thriving, eco-friendly ecosystem. This is one of the core tenets of sustainable purple flowering tall plants gardening practices.

Our Top 10 Purple Flowering Tall Plants for Every Garden Style

Alright, let’s get to the fun part! I’ve grown and loved every plant on this list. Here are my tried-and-true favorites that deliver that incredible vertical purple punch. I’ve included a mix for different light conditions and garden styles.

1. Allium ‘Globemaster’ (Ornamental Onion)

These are the rockstars of the late spring garden. ‘Globemaster’ produces enormous, globe-shaped purple flower heads on tall, sturdy stems. They look like something straight out of a Dr. Seuss book and are absolutely spellbinding when planted in drifts.

  • Height: 3-4 feet
  • Sun: Full Sun
  • Blooms: Late Spring to Early Summer
  • Greeny Gardener’s Tip: Plant allium bulbs in the fall. Their foliage starts to die back as the flowers emerge, so I love to plant them behind perennials like Hostas or Peonies that will fill in and hide the fading leaves.

2. Delphinium ‘Galahad’ or Pacific Giants Mix

For sheer, unadulterated drama, nothing beats a Delphinium. Their towering spires are densely packed with flowers, creating a stunning vertical accent. They are the quintessential cottage garden plant, but they do require a bit of care.

  • Height: 4-6 feet
  • Sun: Full Sun
  • Blooms: Early to Mid-Summer
  • Greeny Gardener’s Tip: Delphiniums are heavy feeders and hate having wet feet. Amend your soil with plenty of compost and ensure it’s well-draining. They almost always need staking, so put your supports in early before they get too tall.

3. Salvia ‘Amistad’ (Friendship Sage)

If I could only choose one plant for non-stop color, ‘Amistad’ would be a top contender. From late spring until the first frost, it produces an astonishing number of deep purple, tubular flowers that hummingbirds adore. It’s a fast grower and incredibly rewarding.

  • Height: 4-5 feet
  • Sun: Full Sun to Part Shade
  • Blooms: Late Spring to Fall
  • Greeny Gardener’s Tip: Don’t be afraid to prune it back by a third in mid-summer if it starts getting leggy. It will reward you with an even bushier plant and a fresh flush of blooms.

4. Liatris spicata (Blazing Star)

A fantastic North American native, Liatris is unique because its fuzzy, bottlebrush-like flowers bloom from the top down. It’s tough, drought-tolerant once established, and a major pollinator magnet, especially for monarch butterflies.

  • Height: 2-4 feet
  • Sun: Full Sun
  • Blooms: Mid to Late Summer
  • Greeny Gardener’s Tip: This plant thrives in average, even poor, soil. Don’t over-fertilize it, or you might end up with weak, floppy stems. It’s a perfect example of a low-maintenance, sustainable purple flowering tall plant.
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5. Verbena bonariensis (Tall Verbena)

This is the fairy godmother of the garden. Its tall, wiry stems are topped with clusters of tiny lavender-purple flowers, creating a transparent, see-through effect. It weaves beautifully between other plants, adding height and texture without blocking the view.

  • Height: 4-6 feet
  • Sun: Full Sun
  • Blooms: Summer to Fall
  • Greeny Gardener’s Tip: It self-seeds readily, which can be a blessing or a curse! I let it pop up where it wants and simply pull out any seedlings that are in the wrong spot. It creates a wonderfully naturalistic look.

6. Perovskia atriplicifolia (Russian Sage)

With its silvery foliage and hazy clouds of lavender-blue flowers, Russian Sage provides incredible texture and color from mid-summer through fall. It’s exceptionally drought-tolerant and loves the heat, making it perfect for a low-water garden.

  • Height: 3-5 feet
  • Sun: Full Sun
  • Blooms: Mid-Summer to Fall
  • Greeny Gardener’s Tip: The key to keeping Russian Sage looking great is a hard prune in early spring. Cut the woody stems back to about 6-8 inches from the ground. This encourages strong, new growth that won’t flop.

7. Baptisia australis (Blue Wild Indigo)

Another powerhouse native plant, Baptisia forms a large, shrub-like clump with beautiful blue-green foliage. In late spring, it sends up impressive spikes of deep indigo-purple flowers that resemble lupines. It’s incredibly long-lived and low-maintenance.

  • Height: 3-4 feet
  • Sun: Full Sun to Part Shade
  • Blooms: Late Spring
  • Greeny Gardener’s Tip: Be patient with Baptisia. It takes a few years to get established, but it’s well worth the wait. Once it’s settled, it develops a deep taproot and is best left undisturbed.

8. Aconitum (Monkshood)

For those shadier spots in the garden, Monkshood is a true gift. It produces stately spires of hooded, deep violet-blue flowers late in the season when many other plants are fading. It adds a touch of mystery and elegance to the shade garden.

  • Height: 3-5 feet
  • Sun: Part Shade
  • Blooms: Late Summer to Fall
  • Greeny Gardener’s Tip: A word of caution: all parts of this plant are highly toxic if ingested. Always wear gloves when handling it and plant it away from areas where children or pets play. That said, it is deer and rabbit resistant!

9. Alcea rosea ‘Nigra’ (Black Hollyhock)

For a dose of old-fashioned charm and incredible verticality, look no further than Hollyhocks. The ‘Nigra’ variety boasts stunning, single flowers in a shade of deep purple so dark it’s nearly black. They are perfect against a sunny wall or the back of a border.

  • Height: 5-8 feet
  • Sun: Full Sun
  • Blooms: Summer
  • Greeny Gardener’s Tip: Hollyhocks can be prone to a fungal disease called rust. To minimize this, ensure good air circulation around the plants and water at the base, not on the leaves.

10. Iris sibirica ‘Caesar’s Brother’ (Siberian Iris)

Siberian Irises have a graceful, upright form with grassy foliage that looks good all season. ‘Caesar’s Brother’ is a classic, beloved for its velvety, deep purple flowers in late spring. They are much easier to grow than their bearded iris cousins.

  • Height: 3-4 feet
  • Sun: Full Sun to Part Shade
  • Blooms: Late Spring
  • Greeny Gardener’s Tip: These irises love consistent moisture, making them a great choice for areas near a downspout or in rain gardens. They form dense clumps that can be divided every few years to share with friends!

Your Ultimate Purple Flowering Tall Plants Guide: Planting for Success

Now that you’ve picked your favorites, let’s talk about how to purple flowering tall plants can be planted for maximum impact. Following a few best practices will set them up for a long and healthy life.

Choosing the Right Spot

This is the most critical step. Pay close attention to the sun requirements for each plant. “Full sun” generally means 6 or more hours of direct sunlight per day. “Part shade” is typically 4-6 hours, ideally with protection from the harsh afternoon sun.

Soil Prep is Everything

Most plants thrive in well-draining soil rich in organic matter. Before planting, I always amend my garden beds with a few inches of compost. This improves soil structure, adds vital nutrients, and helps retain moisture. It’s the single best thing you can do for your garden’s health.

The Art of Spacing

It’s tempting to plant everything close together for an instant full look, but resist! Check the plant tag for its mature width and give it that much space. Good air circulation is key to preventing fungal diseases, one of the more common problems with purple flowering tall plants like Hollyhocks and Delphiniums.

The Essential Care Guide: Nurturing Your Majestic Purple Spires

Once your plants are in the ground, a little ongoing care will keep them looking their best. This is my simple purple flowering tall plants care guide to keep things straightforward.

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Watering Wisely

For the first year, most perennials need consistent watering to establish a strong root system. After that, water deeply but less frequently. This encourages roots to grow down into the soil, making the plant more drought-tolerant. A soaker hose is a fantastic, water-wise tool for this.

To Feed or Not to Feed?

If you’ve prepared your soil with compost, you may not need much additional fertilizer. For heavy feeders like Delphiniums, a top-dressing of compost or a balanced, slow-release granular fertilizer in the spring is beneficial. For natives like Liatris, it’s best to hold off on fertilizer altogether.

Pruning and Deadheading

Deadheading, or removing spent flowers, can encourage many plants like Salvia and Verbena to produce more blooms. For others, like Baptisia and Allium, you can leave the seed heads for winter interest in the garden.

Solving Common Problems with Purple Flowering Tall Plants

Even with the best care, you might run into a few issues. Don’t worry—these are usually easy to fix!

The Dreaded Flop: Staking and Support

This is the number one issue with tall plants. Wind and heavy rain can cause them to bend or break. The secret is to provide support before they need it.

  • Grow-through grids: Place these over plants like Russian Sage or Baptisia in the spring and let them grow up through the grid.
  • Single stakes: Ideal for single-spired plants like Delphiniums and Hollyhocks. Use soft ties to loosely attach the stem to the stake at several points.
  • The “Chelsea Chop”: For some plants, you can cut them back by about a third in late spring (around the time of the Chelsea Flower Show in the UK). This results in a slightly shorter, sturdier plant with more, albeit smaller, flowers.

Pesky Pests and Diseases

The best defense is a healthy plant. Proper spacing for air circulation and watering at the soil level can prevent many fungal issues like powdery mildew. If you do spot pests like aphids, a strong spray of water from the hose is often enough to dislodge them.

Frequently Asked Questions About Purple Flowering Tall Plants

What are the best purple flowering tall plants for beginners?

For a beginner, I’d highly recommend Salvia ‘Amistad’ for its non-stop blooms and easy-going nature, Liatris spicata for its toughness and drought tolerance, and Russian Sage for its incredible resilience. Don’t worry—these flowers are perfect for beginners!

How do I keep my tall plants from falling over?

The key is proactive support! Use stakes, cages, or grow-through grids early in the season before the plants get too tall. Also, avoid over-fertilizing with nitrogen, which can lead to weak, leafy growth that is more prone to flopping.

Can I grow these plants in containers?

Absolutely! Many of these can be grown in large containers. Salvia ‘Amistad’ does wonderfully in a pot. For larger plants like Delphiniums or Hollyhocks, you’ll need a very large, deep container (like a half-whiskey barrel) to accommodate their root systems.

When is the best time to plant tall perennials?

The best times to plant perennials are in the spring or fall. This gives them time to establish their roots during cooler, wetter weather before the stress of summer heat or winter cold sets in.

Your Garden’s Vertical Masterpiece Awaits

There you have it—a complete tour of the most spectacular purple flowering tall plants and all the tips you need to grow them successfully. Adding vertical elements truly is a game-changer, turning a simple garden bed into a dynamic, three-dimensional tapestry of color and life.

Your garden is a canvas, and these majestic purple plants are the bold brushstrokes that will bring it to life. Don’t be afraid to experiment, to move things around, and to find the combinations that make your heart sing.

Now go on, get those gloves dirty and add some vertical magic to your world!

Rimon Chowdhury
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