Nepeta, commonly called catmint, benefits most from a hard cutback immediately after its first flush of flowers fades, typically sometime between late spring and midsummer depending on your climate. That single well-timed shearing does more for the plant’s shape, vigor, and repeat blooming than any other maintenance task. But there are secondary windows that matter too, including a light spring cleanup and decisions about whether to leave growth standing into winter, and the best choice at each point depends on where you garden and which species you grow.
Right After the First Bloom Fades
Most gardeners grow one of the hybrid catmints, such as Nepeta × faassenii ‘Walker’s Low’ or ‘Six Hills Giant,’ which put on a spectacular show of lavender-blue spikes in late spring or early summer. Once roughly two-thirds of those flower spikes have turned brown and the display looks tired, that is the moment to act. Grab hedge shears or hand pruners and cut the entire mound back by about half to two-thirds of its height. The goal is to remove all spent flowers along with the floppy, elongated stems that produced them.
Within a week or two of a good shearing, new growth emerges from lower buds along the remaining stems and from the plant’s crown. In most climates, this produces a second wave of bloom roughly four to six weeks later, sometimes nearly as impressive as the first. If your growing season is long enough, you can repeat the process after the second bloom and occasionally coax a modest third round of flowers before fall.
This post-bloom cutback is the single most important pruning event for catmint. Skipping it does not kill the plant, but it leaves you with a sprawling, open-centered mound that flops over neighboring plants and produces only scattered, sparse rebloom. The difference between a catmint that was sheared and one that was not is dramatic by August.
How Far Down to Cut
A common worry is cutting too aggressively. For the post-bloom shearing, removing half to two-thirds of the plant’s height is safe and standard. You want to leave a compact dome of foliage roughly six to eight inches tall for a typical medium-sized cultivar. This preserves enough leaf area that the plant can photosynthesize and fuel regrowth without relying entirely on stored energy.
That balance between leaf area and stored reserves matters more than people realize. Research on perennial legumes and herbs has shown that vigorous regrowth after cutting depends heavily on carbohydrate reserves in the roots and crown. In studies of Lotus species, plants with substantial root starch recovered strongly after being cut back, while those with low starch reserves produced weak regrowth that sometimes died within days.1PubMed Central. Root Starch Reserves Are Necessary for Vigorous Re-Growth following Cutting Back in Lotus japonicus Catmint is not a legume, but the principle holds across perennial plants: if you cut so hard that no leaves remain and the root reserves are low, recovery stalls. Leaving that basal mound of foliage gives the plant a running start.
If your catmint has become truly woody and bare at the base, with all its green growth at the tips, you may need to cut into semi-woody stems. The plant will usually recover, but it takes longer. In that situation, cutting to about four inches above the soil line and being patient is the safer bet than leaving a tall skeleton of bare sticks.
Spring Cleanup Before New Growth Begins
The second important window comes in early spring, before the new season’s growth has pushed more than a couple of inches. If you left last year’s stems standing through winter, now is the time to cut them down. Trim the old stems to a few inches above the crown, removing the gray, dried-out growth from the previous season. This is a cleanup cut, not a shaping cut. Its purpose is to get dead material out of the way so fresh shoots can emerge cleanly.
Timing this right matters for the plant’s energy budget. Perennial herbs accumulate carbohydrate reserves in their roots during fall, and those reserves decline through winter to reach their lowest point just as spring growth kicks off.2PubMed. Carbohydrate storage and use in an alpine population of the perennial herb, Oxytropis sericea Cutting in early spring, just as buds begin to swell but before the plant has invested much energy in new shoots, avoids wasting any of that limited spring energy budget. If you wait until new growth is already six inches tall and then hack it all off, you are forcing the plant to start over at its most resource-depleted moment.
In mild-winter climates where catmint stays semi-evergreen, the spring cleanup is more of a tidy-up. Remove any brown or tattered leaves and lightly shape the mound, but there is no need to cut to the ground if the plant looks reasonably healthy coming out of winter.
Whether to Leave Growth Standing in Fall
The fall question divides gardeners more than any other aspect of catmint care. One camp cuts everything to the ground after the first hard frost; the other leaves the dried stems standing until spring. Both approaches work, but they serve different purposes.
Leaving stems intact through winter provides some insulation to the crown, which can matter in regions where freeze-thaw cycles are harsh. The standing stems also catch snow, which acts as additional insulation, and they offer habitat for overwintering insects. In colder zones, this hands-off approach is generally the safer choice, especially for species or cultivars that are borderline hardy in your area.
Cutting back in fall tidies the garden and prevents the dead stems from flopping onto neighboring plants over winter. It also reduces the chance that old stems harbor fungal spores heading into the next season. In milder climates where crown damage from cold is not a concern, a fall cutback is perfectly fine and saves you a task in spring. If you do cut in fall, leave two to three inches of stem above the soil line rather than shearing flush with the ground. That stubble marks the crown’s location so you do not accidentally dig into it, and it offers a small buffer of insulation.
Regardless of which camp you fall into, avoid cutting catmint back hard in late summer or early fall while the plant is still actively growing. The regrowth that results will be tender and vulnerable to frost, and the effort of producing it depletes root carbohydrate stores right when the plant should be banking them for winter. Research on perennial crops like lucerne has confirmed that the timing of defoliation directly affects the seasonal cycle of root carbon and nitrogen storage.3European Journal of Agronomy. Seasonal patterns of root C and N reserves of lucerne crops (Medicago sativa L.) grown in a temperate climate were affected by defoliation regime Cutting too late in the season forces the plant to spend reserves on regrowth instead of storing them, which weakens it going into winter.
Why Cutting Back Produces Bushier Growth
If you have ever wondered why a sheared catmint comes back denser than an unsheared one, the answer involves how plants prioritize which buds get to grow. In an uncut stem, the tip exerts a suppressive influence on buds lower down. When you remove that tip, the lower buds are released from suppression and begin growing, each producing a new side shoot.4PubMed Central. Apical Dominance and Shoot Branching. Divergent Opinions or Divergent Mechanisms? Instead of a single tall stem, you get multiple shorter ones. This is the same principle behind pinching back basil or shearing a hedge, and it is why catmint responds so well to being cut: each cut stem can produce two or more replacement shoots, resulting in a denser, more compact mound.
This branching response also explains why catmint that has never been cut develops that characteristic open, floppy habit. The dominant tips keep growing outward and eventually fall under their own weight, while the lower buds stay dormant. Regular shearing prevents that cycle from taking hold by constantly redirecting growth into lower, more numerous shoots.
Adjusting for Climate and Region
The calendar dates for cutback timing shift considerably depending on where you live. In USDA zones 8 and 9, catmint often begins blooming in April, and the first post-bloom shearing might happen in late May or early June. In zone 5 or colder areas, first bloom may not wrap up until late June or early July, pushing the shearing window into July. Rather than following fixed dates, watch the plant itself. When the majority of flower spikes have gone brown and the mound starts looking disheveled, it is time.
Gardeners in hot-summer climates sometimes see catmint go semi-dormant in the worst of the heat, even after being cut back. If your sheared plant sits and sulks through July and August without producing much new growth, do not panic and do not cut again. It is waiting for cooler temperatures. A fall flush of growth and even a late rebloom are common once nighttime temperatures drop in September.
In cool-summer maritime climates, catmint may bloom almost continuously from late spring into fall without a clear break between flushes. In that situation, a mid-season shearing when the plant starts looking ragged, usually around midsummer, keeps it tidy. You may not get a dramatic second bloom so much as a continuation of the first one on fresher stems.
Differences Among Nepeta Species
Not all catmints behave identically, and what you are growing affects how and when you should cut. The most commonly planted catmints are hybrid cultivars of Nepeta × faassenii and selections of Nepeta racemosa. These are the classic mounding, gray-green plants with lavender flower spikes, and everything described above applies directly to them. They respond reliably to post-bloom shearing with vigorous regrowth and repeat bloom.
Nepeta cataria, true catnip, is a different animal. It is taller, coarser, and more upright, with white to pale lavender flowers. It self-seeds aggressively if you let it go to seed, so cutting it back promptly after flowering is less about aesthetics and more about preventing it from colonizing your garden. Catnip also tends to be shorter-lived than the ornamental hybrids and may not rebloom as reliably after shearing. If you grow it for cats rather than looks, you might harvest stems as needed throughout the season rather than doing a single hard cutback.
Nepeta subsessilis, sometimes sold as Japanese catmint, is a larger, more upright species with showier individual flowers. It does not form the dense mound that the faassenii hybrids do, so shearing it into a dome does not make as much sense. Instead, deadhead spent flower spikes individually, cutting each one back to a leaf node. This encourages branching without destroying the plant’s naturally upright architecture.
Nepeta grandiflora, another tall species, falls somewhere in between. It can be cut back hard after its first bloom, but because of its height it may need staking if allowed to regrow to full size. Some gardeners prefer to cut it by only about a third rather than the half-to-two-thirds rule for the shorter hybrids, keeping the regrowth more manageable.
Common Mistakes That Weaken Catmint Over Time
A few patterns tend to produce struggling catmint, and most of them involve pruning timing or technique gone slightly wrong.
- Cutting too late in fall: Shearing catmint in September or October when it is still green and actively storing reserves forces regrowth at the worst time. Either cut before mid-August or wait until after frost and dormancy.
- Never cutting at all: Unpruned catmint becomes woody at the base over several years, and the center of the mound dies out. Annual shearing after bloom keeps the plant rejuvenated and prevents this decline.
- Shearing to the ground in spring too late: Waiting until new growth is well underway and then removing all of it wastes the plant’s spring energy flush and delays bloom by weeks.
- Planting in heavy shade and compensating with harder cuts: Catmint grown in too much shade is already stretched and thin. Hard cutbacks on a light-starved plant stress it further because its depleted root reserves cannot support vigorous regrowth. The fix is more sun, not more pruning.
Overwatering compounds the effects of poor pruning timing. Catmint is drought-tolerant once established, and soggy soil, especially in winter, damages crowns far more than cold alone. A well-drained site forgives pruning mistakes that would be fatal in heavy clay.
Catmint and Companion Planting Considerations
Because catmint’s growth cycle involves a dramatic collapse and regrowth midseason, its neighbors matter. In a mixed border, the gap left by a freshly sheared catmint can be conspicuous. Pairing it with plants that peak in midsummer, such as daylilies, echinacea, or ornamental grasses, covers the gap during the two to three weeks it takes for catmint to refill its space. Conversely, catmint’s early-season bloom coincides with late spring bulbs and early perennials like irises, making them natural companions for the first half of the growing season.
If you grow catmint along path edges or as a ground cover, stagger your shearing. Cut half the plants one week and the other half two weeks later. This avoids the naked-garden look that comes from shearing an entire sweep of catmint at once, and it extends the overall period of bloom by offsetting the regrowth cycles.
Some gardeners interplant catmint with later-emerging perennials that can physically lean into the space catmint vacates after shearing. Russian sage and tall sedums are popular choices because their upright growth fills the visual hole without competing for root space. By the time the catmint regrows and begins its second flush of bloom, these companions are tall enough to hold their own above or beside it.