When to Plant Catmint: Spring to Late-Summer Planting, Lean Soil, Shearing and Dividing Nepeta

Catmint is a group of mint-family perennials in the genus Nepeta; the Almanac counts about 250 species, and catnip (N. cataria) is one of them. The garden catmint most people buy is blue catmint, N. × faassenii, a sterile hybrid first grown by Faassen Nurseries in the Netherlands (NC State, Wisconsin). It makes an 18- to 24-inch mound of gray-green, aromatic leaves that can spread to about 3 feet, with lavender-blue flowers from spring into summer (NC State); Wisconsin says 'Walker's Low' flowers from early summer through fall, and Illinois gives April to August.

When to plant catmint

Use our planting calendar to find your first fall frost date, then count back 4 to 6 weeks for the Almanac's last safe planting date. Spring is easiest because plants have the whole season to root, but the sources agree catmint is forgiving about timing as long as the soil drains.

How to plant catmint

For pots, the Almanac uses a high-quality potting mix with some perlite. NC State and the Almanac list compact cultivars for smaller spaces, such as 'Select Blue' at 15 to 18 inches (NC State) and 'Cat's Pajamas' at about 14 inches (Almanac, Wisconsin); Wisconsin explains that 'Walker's Low', the 2007 Perennial Plant of the Year, is named after an English garden, not its height.

Watering, feeding and shearing

• Water the first season, then only in dry spells (Almanac).
• Skip fertilizer in the ground. The Almanac feeds only container plants, with an annual slow-release fertilizer.
• Shear after the first flush. Wisconsin cuts back by a half to a third, Illinois by half; NC State and the Almanac shear spent flowers for another wave.
• Tidy in spring. Wisconsin shears plants back in spring to keep them compact.
• Divide every few years to reinvigorate the clump (Almanac); Illinois says it seldom needs it.

Catmint in containers

NC State lists catmint for containers and rock-wall crevices, and the Almanac recommends 'Summer Magic' for containers. Use potting mix with perlite and feed once a year with slow-release fertilizer (Almanac). Our reading is to choose a pot with drainage holes and a compact cultivar, and to let the top inch dry between waterings (GardenPal reasoning).

Fall and winter

• Get late plantings in early. At least 4 to 6 weeks before killing frosts (Almanac).
• Cut back in spring. Wisconsin shears plants in spring; leaving the old stems over winter until then is our reading.
• Avoid winter-wet spots, since catmint suffers in soggy soil (Almanac).

Pests and problems

The Almanac says catmint is rarely bothered by pests. NC State says some cultivars resist Phytophthora well while others resist Pythium root rot poorly, and Illinois and Wisconsin mention powdery mildew. Deer leave it alone (NC State, Almanac), and Wisconsin adds rabbits. Catnip is different: Wisconsin says it reseeds readily, and cats can break the stems, so it suggests caging plants or growing them in hanging baskets. NC State says the hybrid is unlikely to reseed.

Catmint around the vegetable garden

Wisconsin says 'Walker's Low' draws bees, butterflies and hummingbirds, and NC State notes that Nepeta repels certain insects, including aphids and squash bugs. That makes it a good edging plant at the sunny, dry edge of a vegetable plot (our reading), though it is no substitute for checking crops. See flowers that attract beneficial insects and companion planting for pest control. Wisconsin pairs it with roses, bee balm, Shasta daisies, blue grasses and soft yellows such as Coreopsis 'Moonbeam'; see bee balm, Shasta daisies and coreopsis. For other dry-border perennials, see lavender and Russian sage. Veronica adds upright blue spikes to the same edge; see when to plant veronica.

Frequently asked questions

When is the best time to plant catmint?

Spring is usual, but you can plant all summer as long as it goes in at least 4 to 6 weeks before your killing frosts (Almanac).

Can I grow catmint from seed?

The popular hybrid, Nepeta × faassenii, is sterile (NC State, Almanac, Wisconsin), so buy plants, divide clumps or root cuttings. Catnip seed can be started indoors a few weeks before the last frost (Wisconsin).

Should I cut back catmint after flowering?

Yes. Wisconsin cuts it back by a half to a third after the first flush, Illinois by half, and the Almanac and NC State shear it for another round of flowers.

Does catmint need fertilizer?

Not in the ground. The Almanac says too easy a life gives fewer flowers and floppy stems; feed containers once a year with slow-release fertilizer.

Is catmint the same as catnip?

No. Both are Nepeta, but catnip is N. cataria, which reseeds readily (Wisconsin), while garden catmint is usually the sterile hybrid N. × faassenii (NC State, Almanac).

Does catmint spread?

The hybrid is sterile and unlikely to reseed (NC State), but clumps widen to about 3 feet (NC State). NC State notes the genus can be a bit weedy, and catnip reseeds readily (Wisconsin).