What is catnip?
Catnip, or catmint, are names commonly used for many species and varieties of Nepeta, a hardy herbaceous perennial. Nepeta cataria is the species that is generally known as the ‘true’ catnip and is said to have the most aromatic leaves. This plant gets its name because cats adore the strong minty scent of the crushed leaves and love to nibble the foliage, sometimes even rolling in the whole plant. Dried catnip leaves are widely used as a stuffing for pet toys so cats can enjoy the fragrance all year round. Catnip is edible and useful for humans, too: the leaves and flowers can be used for flavouring dishes and to make into tea, as an insect and pest repellent. The only drawback with growing catnip is that it is almost guaranteed to entice neighbourhood cats into your garden.
Catnip is an excellent garden plant, blooming through much of summer. Nepeta cataria forms a clump of slender branching stems clothed with toothed grey-green leaves, up to 90cm high and 60cm wide. The flower clusters, made up of many tiny blooms, are violet spotted with white and are borne through summer. The blooms are rich in nectar and entice bees along with a wide selection of pollinating insects. Although this species is decorative, other species and varieties of catmint (Nepeta) have greater ornamental value.
How to grow catnip
Catnip plants are available to buy and plant at any time of year, in a sunny site and well-drained soil, or a large pot. Alternatively grow your own from seed, sowing from spring to autumn. Cut back dead stems during the dormant period and before new shoots start to appear in mid-spring.
Where to grow catnip
Catnip plant needs a free-draining soil and grows best when given plenty of sun. Plant at the edge of a border, in a raised bed, or a large pot. Once established, catnip is tolerant of drought.
How to plant catnip
Plant pot-grown catnip plants at any time of year, with autumn or spring being ideal times to plant. Grow in soil that is poor to moderately fertile, without additional manure or fertiliser. If the soil is heavy and slow to drain, incorporate coarse grit before planting, or grow catnip in a raised bed. Water in immediately after planting and keep watered during dry spells for the first couple of months if planting in spring.
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How to care for catnip
Catnip is easy to grow and needs very little care once established.
How to propagate catnip
Sow seed from spring to late summer, thinly in a small pot or tray of moist seed compost, and lightly covering the seed. Once seedlings are large enough to handle, transplant into individual 9cm pots and grow on without heat until large enough to plant out.
Divide established clumps that are at least 3 years old, whilst dormant, in autumn or early spring.
How to prune catnip
Once the first main flush of flowers has finished, in late in summer, cut back the stems that have bloomed, leaving the young un-flowered growth. This boosts bushy growth and may encourage a repeated flush of flowers.
In autumn the plant dies back to the ground and the dead stems can be cut back at any time before spring. Leaving the dead growth on as long as possible provides shelter for beneficial insects over winter.
Growing catnip – pests and diseases
Nepeta cataria is generally trouble-free from pests and diseases. Powdery mildew may occur in dry summers and is seen as a white coating on the leaves, but does not require action.
Advice on buying catnip
- Nepeta cataria is sometimes available to buy at nurseries and garden centres and may be found either in the perennials section, or with herbs.
- Other species and varieties of catmint are widely available, many of which are more attractive than true catnip
- Always check plants for signs of damage and disease before planting