Giant Catmint Plant

The giant catmint plant is a stunning, low-maintenance perennial that produces masses of lavender-blue flowers from late spring through fall. Loved by bees, butterflies, and hummingbirds, this drought-tolerant beauty thrives in sunny spots and adds months of color to any garden border or cottage-style landscape.

If you have ever walked past a garden buzzing with bees and butterflies, chances are you were near a giant catmint plant. This hardworking perennial has earned its place in countless landscapes for good reason. It asks for little, gives a lot, and looks gorgeous doing it. Whether you are a seasoned gardener or just starting out, this plant deserves a spot in your yard.

In this guide, we will cover everything you need to know about growing, caring for, and designing with the giant catmint plant. From choosing the right variety to solving common problems, you will finish this article ready to plant with confidence. Let us dig in.

Key Takeaways

• Easy to grow: The giant catmint plant thrives in full sun and well-drained soil with minimal fuss once established.
• Long bloom season: Expect flowers from late spring to autumn with a simple mid-summer trim.
• Pollinator magnet: Bees, butterflies, and hummingbirds flock to the nectar-rich blooms all season long.
• Drought tolerant: Deep roots make this perennial a water-wise choice for hot, dry summers.
• Deer and rabbit resistant: Aromatic foliage naturally repels common garden browsers.
• Versatile design uses: Perfect for borders, rock gardens, slopes, and container plantings.
• Simple propagation: Divide clumps in spring or take cuttings in early summer for free new plants.

Quick Answers to Common Questions

How tall does giant catmint plant grow?

Most giant catmint plant varieties reach 24 to 36 inches tall and wide, forming a billowing mound.

When should I cut back giant catmint plant?

Cut back dead stems to 3 to 4 inches in early spring. Shear by half after the first bloom flush in early July for a second show.

Is giant catmint plant invasive?

No. It is a well-behaved clump-former. It does not spread by runners or seed aggressively like catnip.

What soil does giant catmint plant prefer?

Well-drained, gritty or sandy loam. It hates wet clay. Amend heavy soil with compost and coarse sand before planting.

Does giant catmint plant attract cats?

Much less than catnip. Cats may rub on it occasionally but rarely damage it. The nepetalactone content is low in ornamental hybrids.

What Is the Giant Catmint Plant?

The term giant catmint plant usually refers to larger cultivars of Nepeta, a genus in the mint family (Lamiaceae). While standard catmints like Nepeta faassenii stay around 12 to 18 inches tall, the giant types can reach 30 to 36 inches in height and spread just as wide. They form billowing mounds of aromatic, gray-green foliage topped with spikes of lavender-blue, violet, or sometimes white flowers.

Botanical Background

Most giant catmints are hybrids or selections of Nepeta racemosa, Nepeta grandiflora, or crosses between species. The name Nepeta comes from the ancient Etruscan city of Nepete, where the plant grew wild. Unlike its famous cousin catnip (Nepeta cataria), which drives cats into a frenzy, ornamental catmints have much lower levels of nepetalactone. Cats may still rub against them, but they rarely destroy the plant.

Popular Giant Varieties

• ‘Six Hills Giant’: The classic choice. Grows 30 to 36 inches tall with deep violet-blue flowers. Very floriferous and reliable.
• ‘Walker\’s Low’: Despite the name, this one gets tall — 24 to 30 inches. Perennial Plant of the Year in 2007. Lavender-blue blooms.
• ‘Blue Dragon’: A newer introduction with larger, deeper blue flowers and a slightly more upright habit. Reaches 28 to 32 inches.
• ‘Pool Bank’: Soft blue flowers on a broad, mounding plant to 3 feet. Excellent for the middle of a border.
• ‘Dawn to Dusk’: Unique pale pink flowers aging to lavender. Same tough constitution as the blue types.

Ideal Growing Conditions

One reason the giant catmint plant is so beloved is its adaptability. Give it the basics, and it will reward you with months of bloom.

Sunlight Requirements

Full sun is best. That means at least six hours of direct light per day. In hot southern climates, a little afternoon shade is fine and may even extend flowering. Too much shade leads to floppy stems and fewer flowers.

Soil Preferences

Well-drained soil is non-negotiable. The giant catmint plant hates wet feet, especially in winter. Sandy or gritty loam is ideal. Heavy clay? Amend it generously with compost, coarse sand, or fine gravel. A slightly alkaline to neutral pH (6.5 to 7.5) is perfect, but the plant tolerates a range.

Water Needs

Water regularly during the first growing season to establish deep roots. After that, the giant catmint plant is remarkably drought tolerant. In fact, too much water or fertilizer produces weak, floppy growth. Once established, rainfall is often enough except in extreme heat.

Hardiness Zones

Most giant catmints are hardy in USDA zones 3 through 8. Some survive into zone 9 with afternoon shade and good airflow. In the coldest zones, a light winter mulch helps prevent heaving.

Planting Your Giant Catmint Plant

Timing and technique matter. A good start sets the stage for years of performance.

When to Plant

Spring and early fall are the sweet spots. Spring planting gives the whole season to root in before winter. Fall planting works well in zones 5 and warmer, provided you plant at least six weeks before the ground freezes. Avoid planting in the heat of summer unless you can water diligently.

Spacing and Layout

Space plants 24 to 36 inches apart, depending on the variety. They spread! For a mass planting or drift, stagger them in a zigzag pattern rather than a straight line. This looks more natural and fills in faster.

Step-by-Step Planting Guide

1. Dig a hole twice as wide and just as deep as the root ball.
2. Loosen the soil at the bottom and sides.
3. If your soil is heavy, mix in compost and grit at a 50/50 ratio with native soil.
4. Remove the plant from its pot. Gently tease circling roots.
5. Set the plant so the crown sits level with the soil surface.
6. Backfill, firm gently, and water thoroughly.
7. Apply a thin layer of mulch, keeping it away from the crown.

Container Growing

The giant catmint plant does well in large pots (at least 18 inches wide and deep). Use a gritty, well-draining potting mix — think cactus mix blended with compost. Water when the top inch of soil feels dry. Feed once in spring with a slow-release fertilizer. Overwinter pots in a sheltered spot or sink them into the ground.

Seasonal Care and Maintenance

Low maintenance does not mean no maintenance. A few timely tasks keep your giant catmint plant looking its best.

Spring Cleanup

In early spring, cut back all dead stems to about 3 to 4 inches above ground. Do this before new growth emerges. It is the single most important task. Skip it, and you get a tangled mess of old and new stems.

The Chelsea Chop (Mid-Summer Rejuvenation)

Around late June or early July, after the first big flush fades, shear the whole plant back by one-third to one-half. This is often called the Chelsea Chop. It sounds drastic, but it works wonders. You will get a fresh mound of foliage and a second heavy bloom in August through October. Use hedge shears or sharp pruners. Water well after cutting.

Deadheading

If you do not do the Chelsea Chop, deadhead spent flower spikes individually. This encourages rebloom but is more time-consuming. The shear method is faster and gives a neater shape.

Fertilizing

Less is more. A shovel of compost around the base in spring is plenty. Avoid high-nitrogen fertilizers. They promote soft, floppy growth that flops in rain. If your soil is very poor, a light application of balanced organic fertilizer (like 5-5-5) in early spring is okay.

Watering Established Plants

Water deeply but infrequently. Let the soil dry between waterings. In a typical summer, established plants need supplemental water only during prolonged dry spells. Overwatering is the most common killer.

Dividing

Every three to four years, the center of the clump may die out or flowering declines. Early spring is the best time to divide. Dig up the whole plant. Use a sharp spade or knife to cut into sections, each with roots and shoots. Replant the vigorous outer pieces. Discard the woody center. Water in well.

Designing with Giant Catmint Plant

The giant catmint plant is a designer’s dream. Its soft color, billowy texture, and long season make it incredibly versatile.

Color Companions

The lavender-blue flowers pair beautifully with almost anything. Some winning combos:

• Roses: Classic pairing. The blue softens rose thorns and hides bare canes. Try with pink, yellow, or white shrub roses.
• Salvias: Salvia nemorosa ‘Caradonna’ or ‘May Night’ echo the spike shape in deeper purple.
• Yarrow: Flat heads of Achillea ‘Moonshine’ (yellow) or ‘Paprika’ (red) contrast the vertical spikes.
• Ornamental grasses: Pennisetum ‘Hameln’, Calamagrostis ‘Karl Foerster’, or Schizachyrium add movement and winter structure.
• Echinacea: Coneflowers in pink, white, or orange extend the pollinator buffet.
• Alliums: Purple globes of Allium ‘Globemaster’ or ‘Purple Sensation’ rise above the catmint mound in late spring.

Garden Styles

• Cottage garden: Let it spill over paths and mingle with foxgloves, delphiniums, and hardy geraniums.
• Mediterranean / gravel garden: Perfect with lavender, rosemary, thyme, and cistus in a sunny, well-drained bed.
• Pollinator meadow: Drift it through a matrix of native grasses and wildflowers.
• Modern minimalist: Plant in a grid or linear row for a clean, architectural look.
• Slope stabilization: The spreading roots hold soil on banks. Mix with creeping juniper or sedum.

Edge and Border Uses

Use the giant catmint plant to soften hard edges — along a stone wall, sidewalk, or driveway. It billows over hardscape beautifully. In a mixed border, place it in the middle ground. Taller plants behind (delphiniums, hollyhocks), shorter in front (dianthus, sedum, heuchera).

Container Combinations

In a large pot, pair a single giant catmint plant with a trailing annual like white bacopa or silver dichondra. Add a thriller — maybe a purple fountain grass or a small ornamental pepper — for height. The catmint fills the middle with months of bloom.

Pollinators and Wildlife Benefits

If you want a garden alive with buzz and flutter, the giant catmint plant is a must-have.

Bees

Honeybees, bumblebees, and solitary native bees all visit constantly. The flower structure is perfect for them. Long bloom means reliable forage when other plants are between flushes.

Butterflies

Swallowtails, monarchs, painted ladies, and skippers sip nectar throughout the day. Plant in drifts of three or more to create a visible target.

Hummingbirds

They love the tubular flowers. You will see them darting from spike to spike, especially in the morning and late afternoon.

Beneficial Insects

Hoverflies, parasitic wasps, and lacewings visit the flowers. Their larvae eat aphids and other pests. The giant catmint plant is a biological control station disguised as a pretty perennial.

Deer and Rabbit Resistance

The strong, minty aroma of the foliage deters browsing. In high-pressure areas, they may nibble new spring growth, but established plants are rarely damaged. This makes the giant catmint plant a reliable choice for unfenced gardens.

Common Problems and Solutions

Tough as it is, the giant catmint plant can have issues. Here is how to spot and fix them.

Floppy, Leggy Growth

Cause: Too much shade, too much water, too much fertilizer, or overcrowding.
Fix: Move to full sun. Cut back on water and fertilizer. Do the Chelsea Chop. Divide crowded clumps.

Powdery Mildew

Cause: Humid conditions, poor air circulation, overhead watering.
Fix: Space plants properly. Water at the base. Thin stems in spring to improve airflow. Remove badly affected leaves. In severe cases, spray with a homemade baking soda solution (1 tsp baking soda + 1 quart water + few drops dish soap) or a commercial fungicide labeled for ornamentals.

Root Rot

Cause: Poor drainage, overwatering, heavy clay soil.
Fix: Prevention is key. Amend soil at planting. Do not mulch heavily right against the crown. If a plant collapses, dig it up. Trim rotten roots. Replant in a better spot or a raised bed.

Spider Mites

Cause: Hot, dry, dusty conditions.
Fix: Blast with a strong jet of water every few days. Increase humidity. Insecticidal soap or neem oil works for heavy infestations.

Cat Damage

Cause: Neighborhood cats rolling, chewing, or napping.
Fix: Most ornamental catmints are low in nepetalactone. If cats are a problem, try Nepeta ‘Blue Dragon’ or ‘Walker\’s Low’, which seem less attractive. Or place a few twiggy branches over the plant in spring until it toughens up.

Center Die-Out

Cause: Age. The plant becomes woody in the middle after 3-4 years.
Fix: Divide in early spring. Replant the outer vigorous sections.

Propagation Methods

Want more giant catmint plant for free? You have three easy options.

Division

Best done in early spring as new growth appears. Dig the clump. Cut into pieces with a sharp spade or knife. Each division needs roots and several shoots. Replant immediately. Water well. This is the fastest way to get mature-sized plants.

Softwood Cuttings

Take cuttings in late spring to early summer from non-flowering shoots. Cut 4 to 6 inch pieces just below a node. Strip lower leaves. Dip in rooting hormone (optional but helpful). Stick in a pot of moist perlite-vermiculite mix or sandy potting soil. Cover with a plastic bag or dome. Place in bright, indirect light. Roots form in 2 to 3 weeks. Pot up and grow on.

Seed

Species catmints come true from seed. Hybrids like ‘Six Hills Giant’ and ‘Walker\’s Low’ do not — seedlings will vary. If you want to experiment, collect seed in late summer. Sow in fall outdoors or in spring indoors. Barely cover. Germination takes 10 to 20 days at 65 to 70°F. Transplant seedlings when they have two sets of true leaves.

Giant Catmint Plant vs. Catnip: What Is the Difference?

Gardeners often confuse the two. Here is the quick breakdown.

• Catnip (Nepeta cataria): Weedy, 2 to 3 feet tall, white flowers with purple spots, coarse foliage. High nepetalactone. Cats go crazy. Spreads aggressively by seed. Not ornamental.
• Giant catmint plant (ornamental Nepeta hybrids): Tidy mounds, showy lavender-blue flowers, aromatic but refined foliage. Low nepetalactone. Cats may rub but rarely destroy. Clump-forming, not invasive. Highly ornamental.

If you want a pretty garden plant that pollinators love, choose the giant catmint plant. If you want to entertain your cat, grow catnip in a pot away from the border.

Harvesting and Uses

While grown mainly for ornament, the giant catmint plant has other uses.

Cut Flowers

Stems last 5 to 7 days in a vase. Cut when half the flowers on a spike are open. Strip lower leaves. Change water daily. The blue color holds well.

Dried Flowers

Hang small bunches upside down in a dark, airy place. They dry to a soft gray-blue. Use in wreaths or potpourri.

Herbal Tea

The leaves make a mild, minty tea. Steep a few fresh leaves in hot water for 5 minutes. It is relaxing and caffeine-free. Pregnant women should avoid large amounts.

Cat Enrichment

If your cat enjoys it, stuff dried leaves into a cloth toy. Much less messy than loose catnip.

Frequently Asked Questions

How fast does giant catmint plant grow?

Fast. A spring-planted quart pot reaches near-mature size by late summer. It fills its allotted space (2 to 3 feet wide) in one to two seasons.

Does giant catmint plant spread aggressively?

No. It is a clump-former. It expands slowly by widening its crown. It does not run by rhizomes or seed aggressively like catnip or some mints.

Can I grow giant catmint plant in shade?

It tolerates light shade (4 to 6 hours sun) but flowers less and gets floppy. Full sun is strongly recommended for best form and bloom.

Why is my giant catmint plant not flowering?

Usually too much shade, too much nitrogen fertilizer, or the plant needs dividing. Also, a hard late frost can kill flower buds. Ensure full sun, skip fertilizer, and divide if the center is woody.

Is giant catmint plant evergreen?

No. It is herbaceous perennial. Foliage dies back in winter. In mild zones, a low tuft of basal leaves may persist.

Can I grow giant catmint plant indoors?

Not long-term. It needs full sun, seasonal dormancy, and good airflow. It will get leggy and attract spider mites indoors. Grow it outside.

Conclusion

The giant catmint plant is one of those rare perennials that checks every box. Beautiful? Yes. Long-blooming? Absolutely. Low maintenance? You bet. Pollinator-friendly? A superstar. Deer resistant? Check. Versatile in design? Endlessly.

Whether you tuck one into a sunny border, mass five along a path, or let it spill from a big terra cotta pot, this plant delivers. Give it sun, drainage, and a mid-summer haircut, and it will bloom its heart out for months. Year after year.

If you have not grown it yet, this is the season. Pick a variety that catches your eye, find a sunny spot, and plant. Your garden — and the bees — will thank you.

Frequently Asked Questions

How do I keep my giant catmint plant from flopping over?

Plant in full sun, avoid over-fertilizing, and do the Chelsea Chop in early July. Shearing back by half after the first bloom creates a sturdier, more compact plant with fresh flowers.

Can giant catmint plant survive winter in zone 3?

Yes, most giant catmint plant varieties are hardy to USDA zone 3. Apply a light mulch of straw or shredded leaves after the ground freezes for extra protection in the coldest areas.

What is the difference between Walker’s Low and Six Hills Giant catmint?

Both are large, but ‘Six Hills Giant’ grows slightly taller (30 to 36 inches) with deeper violet-blue flowers. ‘Walker\’s Low’ reaches 24 to 30 inches with lavender-blue blooms and a slightly longer bloom season.

Should I deadhead giant catmint plant?

You can deadhead individual spent spikes, but shearing the whole plant back by half in mid-summer (the Chelsea Chop) is faster and produces a better second flush of flowers and neat foliage.

Can I divide giant catmint plant in the fall?

Spring is best for division. Fall division risks winter heaving and loss before roots establish. If you must divide in fall, do it at least 6 weeks before the ground freezes and mulch well.

Why are the leaves on my giant catmint plant turning yellow?

Yellow leaves usually mean overwatering or poor drainage. Let the soil dry between waterings. If in heavy clay, improve drainage or move the plant. Nutrient deficiency is rare but possible in very sandy soil — add compost.