How Far Apart Should You Plant Catmint

Plant catmint 18 to 24 inches apart for most standard varieties to ensure good air circulation and room to spread. Dwarf types need only 12 to 15 inches while larger cultivars like ‘Six Hills Giant’ require up to 36 inches. Proper spacing prevents disease, encourages fuller blooms, and makes maintenance easier.

If you have ever wandered through a sunny garden in early summer, you have likely seen catmint. It forms soft mounds of gray-green leaves topped with spikes of lavender-blue flowers. Bees love it. Cats love it. Gardeners love it because it asks for very little and gives back so much. But there is one question that trips up both new and seasoned growers. How far apart should you plant catmint to get that lush, healthy look without creating a tangled mess?

The answer is not a single number. It depends on the variety you choose, the soil you have, the climate you live in, and the look you want. Plant them too close and you invite powdery mildew, weak stems, and a maintenance headache. Plant them too far apart and you wait years for the bed to fill in, leaving gaps for weeds to move in. This guide walks you through everything you need to know to space your catmint perfectly from day one.

Key Takeaways

• Standard spacing is 18 to 24 inches: Most catmint varieties thrive with this distance between plants.
• Dwarf varieties need less room: Compact types like ‘Little Trudy’ only require 12 to 15 inches of space.
• Large cultivars need more space: Varieties such as ‘Six Hills Giant’ should be planted 30 to 36 inches apart.
• Air circulation prevents disease: Proper spacing reduces humidity around foliage and stops fungal problems.
• Consider mature width not pot size: Space plants based on their full-grown spread, not their current container size.
• Row planting differs from mass planting: Rows need wider spacing between rows than between plants in the row.
• Divide crowded plants every few years: Regular division maintains healthy spacing and rejuvenates older clumps.

Quick Answers to Common Questions

How far apart should you plant catmint ‘Walker’s Low’?

Plant ‘Walker’s Low’ catmint 18 to 24 inches apart on center. This variety reaches 24 to 30 inches wide at maturity. At 18-inch spacing, plants merge into a solid drift by midsummer. At 24 inches, they remain distinct mounds that touch at the edges.

Can you plant catmint too close together?

Yes. Planting catmint too close causes poor air circulation, leading to powdery mildew, weak stems, center die-out, and fewer flowers. Crowded plants also compete for water and nutrients. Always space for mature width, not current pot size.

What is the spacing for dwarf catmint varieties?

Dwarf catmint varieties like ‘Little Trudy’, ‘Blue Wonder’, and ‘Purrsian Blue’ should be planted 12 to 15 inches apart. These compact plants reach only 10 to 12 inches wide at maturity, so they can be spaced closer than standard varieties.

Does catmint spread aggressively like mint?

No. Catmint (Nepeta) is a clump-forming perennial that expands slowly from the crown. It does not run underground with invasive rhizomes like true mint (Mentha). It stays where you plant it and only needs division every few years to maintain vigor.

How far from a path edge should I plant catmint?

Plant catmint back from path edges by at least half its mature width plus six inches. For a 24-inch wide variety, place the planting hole center 18 to 20 inches from the pavement. This prevents floppy stems from blocking the path after rain.

Understanding Catmint Growth Habits

Before you measure out any holes, it helps to know how catmint actually grows. Catmint, or Nepeta, is a perennial herb in the mint family. Unlike its aggressive cousin spearmint, catmint does not run underground with invasive runners. Instead, it forms a clump that expands slowly outward from the center. Each year the crown gets a little wider. The stems rise up and then arch outward, creating a fountain shape.

The Clump-Forming Nature

Most catmint varieties are clump-formers. This means the plant stays more or less where you put it. The crown diameter increases each season. A young plant in a four-inch pot might be six inches wide. By year three, that same plant could be two feet across. The stems do not root where they touch the ground. This is a key difference from true mints. You do not need to worry about catmint taking over your garden beds.

Mature Size Varies by Variety

Catmint varieties range from tiny rock garden plants to large shrubby perennials. Nepeta x faassenii cultivars like ‘Walker’s Low’ reach about 24 to 30 inches tall and wide. The popular ‘Cat’s Meow’ stays neater at 18 to 20 inches. Dwarf types like ‘Little Trudy’ or ‘Blue Wonder’ top out at 10 to 12 inches. At the other end, ‘Six Hills Giant’ and ‘Select Blue’ can spread 36 inches or more. Knowing the mature width of your specific variety is the single most important factor in deciding how far apart should you plant catmint.

Seasonal Growth Cycle

Catmint emerges early in spring. By late spring it is flowering heavily. After the first flush, the plant can look a bit tired. Many gardeners shear it back by half. This triggers fresh growth and a second bloom in late summer. The plant goes dormant in winter. In spring, new shoots push up from the crown. The plant does not move. It just gets wider. This predictable cycle makes spacing calculations reliable.

Standard Spacing Guidelines by Variety

Now let us look at specific numbers. These are the spacing recommendations used by nursery professionals and landscape designers. They assume you want the plants to touch at maturity, creating a continuous mass of foliage and flowers. If you prefer distinct individual specimens with visible gaps, add six to twelve inches to these numbers.

Dwarf and Compact Varieties (10 to 15 inches mature width)

Varieties: ‘Little Trudy’, ‘Blue Wonder’, ‘Junior Walker’, ‘Kit Cat’, ‘Purrsian Blue’.

Recommended spacing: 12 to 15 inches apart on center.

These small plants are perfect for the front of the border, rock gardens, or edging a path. Because they stay neat, you can plant them closer. At 12 inches, they will knit together by the end of the first growing season. At 15 inches, you might see a little soil between them the first year. Both work well. The tighter spacing gives faster coverage. The wider spacing saves money on plants.

Medium Varieties (18 to 24 inches mature width)

Varieties: ‘Walker’s Low’, ‘Cat’s Meow’, ‘Cat’s Pajamas’, ‘Dropmore’, ‘Blue Dragon’.

Recommended spacing: 18 to 24 inches apart on center.

This is the sweet spot for most garden situations. ‘Walker’s Low’ is the classic example. It was named Perennial Plant of the Year in 2007. At 18 inches, the plants merge into a solid drift by midsummer of year one. At 24 inches, they remain distinct mounds that touch at the edges. This spacing also works well for Nepeta racemosa types. If you are asking how far apart should you plant catmint for a typical garden border, 20 inches is a safe default.

Large and Vigorous Varieties (30 to 40 inches mature width)

Varieties: ‘Six Hills Giant’, ‘Select Blue’, ‘Souvenir d’Andre Chaudron’, Nepeta sibirica, Nepeta grandiflora ‘Dawn to Dusk’.

Recommended spacing: 30 to 36 inches apart on center.

These are statement plants. ‘Six Hills Giant’ can hit three feet tall and four feet wide in rich soil. Give them room. If you crowd them, the centers become woody and bare. The flowers only appear on the outer edges. At 36 inches, each plant has space to develop its natural fountain shape. You can plant spring bulbs or annuals in the gaps while the catmint fills in.

Species Types and Seed-Grown Plants

If you are growing catmint from seed, or planting species like Nepeta cataria (true catnip) or Nepeta mussinii, expect more variation. Seed-grown plants are not clones. One might spread 18 inches. Its sibling might spread 28 inches. Space seed-grown plants at 24 inches to be safe. True catnip (Nepeta cataria) is rangier and less ornamental. Give it 24 to 30 inches. It also self-sows aggressively, so deadhead it unless you want volunteers everywhere.

Factors That Affect Planting Distance

The variety label gives you a starting point. But your specific garden conditions can shift the ideal spacing. Here are the main factors to weigh.

Soil Fertility and Moisture

Catmint prefers lean, well-drained soil. In rich, moist soil, it grows larger and floppier. In poor, dry soil, it stays compact. If you have heavy clay amended with compost, or you irrigate regularly, your plants will exceed the label dimensions. Add six inches to the recommended spacing. If you have sandy, nutrient-poor soil and you water sparingly, you can subtract three to six inches. The plants will naturally stay smaller.

Sun Exposure

Full sun (six plus hours) produces the most compact, floriferous plants. In part shade (four to six hours), catmint stretches toward the light. Stems become longer, weaker, and the plant spreads wider. In shade, increase spacing by six to twelve inches. Also expect fewer flowers and more powdery mildew risk. Good air circulation becomes even more critical in lower light.

Climate and Growing Season Length

In cool climates with short summers (zones 3 to 5), catmint grows more slowly. It may never reach the maximum width listed on the tag. You can plant slightly closer. In warm climates with long growing seasons (zones 7 to 9), catmint can grow almost year-round. It will hit full size faster and may exceed it. Space wider in the South. In humid climates, wider spacing is essential for disease prevention. The extra air flow helps foliage dry quickly after rain or dew.

Garden Design Intent

Are you planting a formal edging? A naturalistic drift? A single specimen in a mixed border? For a formal edge where you want a continuous line, use the tighter end of the range. For a naturalistic drift where plants intermingle with neighbors, use the wider end. For a specimen plant, give it the full mature width plus a foot of clear space on all sides. This lets the plant show its true form.

Companion Plants

Catmint plays well with others. But neighbors matter. If you plant catmint next to aggressive spreaders like bee balm or obedient plant, give the catmint extra room. It will lose a competition for space. If the neighbors are well-behaved clumpers like salvia, coneflower, or ornamental grasses, standard spacing works. Also consider height. Tall neighbors shade catmint, causing stretching. Short neighbors get smothered if catmint flops. Match heights or stake the catmint.

Planting Techniques for Proper Spacing

You have your variety. You have your spacing number. Now how do you actually get them in the ground at the right distance? Here are practical methods.

Measure on Center

Plant spacing is always measured “on center.” This means from the center of one plant’s crown to the center of the next plant’s crown. It is not edge-to-edge. If the tag says 18 inches, measure 18 inches from the middle of the root ball of plant one to the middle of the root ball of plant two. Use a tape measure. Do not eyeball it. Small errors compound down a row.

Use a Spacing Stick or Board

Cut a piece of scrap wood or PVC pipe to your target spacing. For 18-inch spacing, cut an 18-inch stick. Place the first plant. Lay the stick against its center. Place the second plant at the other end. Move the stick and repeat. This is much faster than measuring each gap individually. For mass plantings, make a triangular spacing jig. An equilateral triangle with sides equal to your spacing lets you offset rows for a natural look.

Triangular vs. Rectangular Grid

Rectangular grids (rows and columns) are easier to lay out. Triangular spacing (staggered rows) looks more natural and provides slightly better air circulation. In a triangular grid, the distance between rows is 0.866 times the plant spacing. For 18-inch spacing, rows are about 15.5 inches apart. Plants in adjacent rows are offset by half the spacing (9 inches). This creates a denser fill with the same number of plants.

Planting Hole Preparation

Dig each hole twice as wide as the pot and just as deep. Loosen the soil at the bottom. Do not amend the backfill heavily. Catmint prefers lean conditions. If your soil is terrible, mix in a little compost. But do not create a “bathtub effect” where the amended hole holds water and the surrounding clay does not. Set the plant so the crown sits at soil level. Backfill. Firm gently. Water well.

Mulching After Planting

Apply two inches of mulch after planting. Keep mulch away from the crown. Mulch conserves moisture and suppresses weeds while the plants establish. It also visually defines the spacing. You can see the pattern. As the plants grow, they will cover the mulch. Replenish annually. Avoid heavy wood chips. Pine straw, shredded leaves, or compost work better for catmint.

Common Spacing Mistakes to Avoid

Even experienced gardeners make these errors. Learn from them.

Planting Based on Pot Size

This is the number one mistake. You buy a quart pot. The plant is six inches wide. You plant them six inches apart. By July, they are a solid mat. By next year, the centers are dying out. Always space for mature width, not current size. Look at the plant tag. Check the variety online. Trust the mature dimensions.

Ignoring Variety Differences

You buy three different catmints. You plant them all at 18 inches. Two years later, ‘Six Hills Giant’ has swallowed ‘Little Trudy’. Group varieties by mature size. Plant all the dwarfs together. All the mediums together. All the giants together. Or transition gradually from front to back of the border.

Crowding for Instant Effect

Clients want the garden to look full immediately. Landscapers sometimes plant too tight to please them. This backfires. Crowded catmint gets powdery mildew. Stems rot at the base. Flowers are smaller. You end up dividing or removing plants within a year. Be patient. Use annuals or fast-growing perennials like Gaura or Verbena bonariensis to fill gaps the first season.

Forgetting Maintenance Access

You need to reach the plants to deadhead, shear, divide, and weed. If you plant a solid block four feet wide with no path, you cannot maintain the center without stepping on plants. Leave stepping stones or a narrow access path every three to four feet in large plantings. Or plant in drifts no deeper than three plants so you can reach the back from the front.

Not Accounting for Flop

Catmint stems arch. After rain, they lie flat. A plant with a 24-inch crown may have stems that reach 36 inches horizontally when wet. If you plant 24 inches from a path edge, the flopped stems block the path. Set plants back from edges by at least half their mature width plus six inches. For a 24-inch variety, that means 18 inches from the path edge.

Maintaining Proper Spacing Over Time

Spacing is not a one-time decision. Catmint grows. Gardens change. Here is how to keep the spacing right for years.

Annual Shearing

After the first bloom fades (usually late June), shear the whole plant back by one-third to one-half. Use hedge shears or a string trimmer. This removes spent flowers, prevents seeding, and forces fresh basal growth. The plant stays denser and more compact. It also reduces the flop. Shearing effectively “resets” the plant’s width each year. An unsheared plant spreads wider and opens up in the center.

Division Every Three to Four Years

Catmint centers eventually become woody and die out. The plant becomes a ring with a dead middle. This happens faster when plants are crowded. Dig the whole clump in early spring or fall. Cut it into sections with a sharp spade or knife. Each division needs roots and shoots. Replant the best pieces at the correct spacing. Discard the woody center. Division rejuvenates the plant and gives you free plants for elsewhere.

Managing Self-Sowing

Some catmint varieties self-sow modestly. ‘Walker’s Low’ is sterile. ‘Six Hills Giant’ rarely seeds. But species types and some cultivars drop seed. Seedlings appear near the mother plant. If you let them grow, they tighten the spacing. Pull unwanted seedlings in spring. Or transplant them to fill gaps. Deadheading after the first bloom prevents most seeding.

Adjusting for Neighbor Growth

Your catmint spacing was perfect. But the ornamental grass next to it has doubled in size. The rose behind it casts more shade each year. Gardens are dynamic. Reassess spacing every few years. If a neighbor crowds your catmint, you may need to move one or the other. Fall is the best time to transplant catmint. Spring works too if you water diligently.

Replacing Lost Plants

Sometimes a plant dies. Winter kill. Vole damage. Mystery reasons. You have a gap. Do not just stuff a new plant in the hole if the neighbors have expanded. The neighbors now occupy more than their allotted space. Either divide a neighbor to fill the gap, or buy a new plant and accept it will be crowded for a year until you divide the neighbors. Better yet, plan for this. Keep a few extra plants in a nursery bed.

Special Situations: Containers, Slopes, and Path Edges

Standard spacing rules shift in certain scenarios.

Container Planting

In pots, you can plant closer because you control water and nutrients. But root space is limited. For a 12-inch pot, one dwarf plant or one medium plant. For an 18-inch pot, one large plant or three dwarfs at 6-inch spacing. For a 24-inch trough, three mediums at 8-inch spacing. Container plants need more frequent division. They exhaust soil faster.

Planting on Slopes

On a slope, erosion is the enemy. You want faster coverage. Plant at the tight end of the range. Stagger rows in a triangular grid. Mulch heavily with shredded bark that locks together. Use jute netting on steep slopes until plants establish. Catmint roots hold soil well once established. The arching stems also slow surface runoff.

Edging Paths and Driveways

This is where flop matters most. Plant back from the edge. For a 24-inch variety, the planting hole center should be 18 to 20 inches from the pavement. The mature plant will arch over the edge softly without blocking passage. For a formal edge, use a dwarf variety at 12-inch spacing right at the edge. Shear it into a low hedge. It tolerates this well.

Underplanting Roses and Shrubs

Catmint is a classic rose companion. It hides bare knees. It attracts beneficial insects. But roses need air flow too. Plant catmint at least 18 inches from the rose crown. Use medium varieties. Shear the catmint after its first bloom so it does not compete with the rose’s second flush. Avoid large catmint varieties under roses. They get too tall and create humidity.

Designing with Catmint Spacing in Mind

Spacing is a design tool. It shapes how the garden looks and functions.

Creating Drifts and Rivers

Naturalistic designers like Piet Oudolf use catmint in long drifts. They plant in groups of odd numbers (3, 5, 7, 9) at standard spacing. The groups overlap slightly. This creates a river of blue. The key is repetition. Same variety. Same spacing. Repeated down the border. The rhythm leads the eye.

Matrix Planting

In matrix planting, catmint forms the “ground cover” layer. It is planted at consistent spacing (usually 18 to 24 inches) across the whole bed. Taller perennials (coneflowers, grasses, phlox) are plugged into the matrix at wider intervals. The catmint knits together and suppresses weeds. The taller plants emerge through it. This only works with consistent, correct spacing.

Formal Geometric Layouts

Knot gardens, parterres, and formal herb gardens use catmint as a low hedge. Here spacing is tight. 12 inches for dwarfs. Plants are sheared monthly. The tight spacing forces upright growth. The result is a crisp line. This is high maintenance. It requires rich soil and regular water to sustain the constant regrowth.

Pollinator Gardens

If your goal is maximum nectar, spacing affects flower density. Closer spacing (tight end of range) produces more flower spikes per square foot. But only if air circulation is adequate. In humid areas, wider spacing with more varieties extends the bloom season. Mix early, mid, and late blooming catmints. Stagger the spacing so they interlock.

Troubleshooting Spacing Problems

Even with planning, issues arise. Here is how to fix them.

Plants Are Too Crowded

Symptoms: Powdery mildew on lower leaves. Weak, spindly stems. Fewer flowers. Dead centers. Solution: In spring or fall, dig every other plant. Replant elsewhere or give away. The remaining plants will fill the gaps in one season. If the whole bed is crowded, divide everything and replant at correct spacing.

Gaps Are Not Filling In

Symptoms: Bare soil visible after two years. Weeds taking over. Plants staying small. Solution: Check soil. Catmint in compacted clay or deep shade will not spread. Improve drainage. Limb up trees. Or accept the gaps and mulch heavily. You can also interplant with low groundcovers like Thymus or Sedum.

Plants Are Flopping Into Neighbors

Symptoms: Stems lying on adjacent plants. Smothering smaller neighbors. Solution: Install grow-through supports in early spring. Or shear the catmint earlier (when 12 inches tall) to reduce height. Or move the neighbor. Or stake individual stems with bamboo and twine.

Center Die-Out

Symptoms: Green ring, dead brown center. Solution: This is natural aging. Dig the plant. Divide. Replant healthy outer sections. Discard the center. Do this every three to four years preventatively.

Quick Reference Spacing Chart

Keep this handy when you shop or plant.

• ‘Little Trudy’, ‘Blue Wonder’, ‘Junior Walker’, ‘Kit Cat’, ‘Purrsian Blue’: 12 to 15 inches
• ‘Walker’s Low’, ‘Cat’s Meow’, ‘Cat’s Pajamas’, ‘Dropmore’, ‘Blue Dragon’: 18 to 24 inches
• ‘Six Hills Giant’, ‘Select Blue’, ‘Souvenir d’Andre Chaudron’, N. sibirica, N. grandiflora: 30 to 36 inches
• Seed-grown, N. cataria, N. mussinii: 24 to 30 inches
• Rich soil, irrigation, part shade, humid climate: Add 6 inches
• Poor soil, dry, full sun, cool climate: Subtract 3 to 6 inches
• Container (12″ pot): 1 plant
• Container (18″ pot): 1 large or 3 dwarf
• Path edge (24″ variety): Plant center 18 to 20 inches back
• Under roses: 18 inches from rose crown, medium variety

Conclusion

Knowing how far apart should you plant catmint changes everything. It is the difference between a garden that looks good for three weeks and one that looks good for three decades. The rules are simple. Match spacing to mature width. Adjust for your conditions. Measure on center. Use a spacing stick. Be patient the first year. Shear annually. Divide every few years. Do these things and your catmint will reward you with waves of blue flowers, clouds of bees, and the quiet satisfaction of a garden that works.

Next time you stand in the nursery holding a pot of ‘Walker’s Low’, you will not guess. You will know. Eighteen to twenty-four inches. Center to center. Done. Your future self, shearing happy plants in June, will thank you.

Frequently Asked Questions

How far apart should you plant catmint in a container?

In a 12-inch container, plant one dwarf catmint or one medium variety. In an 18-inch container, plant one large variety or three dwarf plants spaced 6 inches apart. Container plants need more frequent division and feeding than in-ground plants.

What happens if I plant catmint in the shade?

In shade, catmint stretches toward light, becoming leggy and wider than normal. Flower production drops significantly. Powdery mildew risk increases. If you must plant in part shade, increase spacing by 6 to 12 inches and expect a looser, less floriferous plant.

Can I plant different catmint varieties together?

Yes, but group them by mature size. Plant all dwarf varieties together, all medium together, all large together. Mixing sizes causes larger varieties to smother smaller ones. Transition gradually from front to back of the border if using multiple sizes.

How often should I divide catmint to maintain spacing?

Divide catmint every three to four years in early spring or fall. Signs it needs division include a dead woody center, reduced flowering, and the plant exceeding its allotted space. Division rejuvenates the plant and gives you free plants for other areas.

Should I space catmint differently for a formal hedge look?

For a formal sheared hedge, use dwarf varieties at 12-inch spacing. Shear monthly during the growing season. This high-maintenance approach forces dense upright growth. Standard varieties are too large and floppy for tight formal hedging.

How far apart should you plant catmint from roses?

Plant catmint at least 18 inches from the rose crown. Use medium varieties (18 to 24 inches wide) and shear after the first bloom. This prevents competition for air and light while still providing the classic rose-catmint companion planting benefits.