Xeriscape Gardens

Pycnanthemum tenuifolium Care: Narrowleaf Mountain Mint

Pycnanthemum tenuifolium flowers

Pycnanthemum tenuifolium is a hardy and adaptable plant that you can plant in your herb garden, along your garden borders, and between rocks or as a xeriscaping plant. All parts of this plant, when crushed, have a strong fragrance of mint. The dried leaves of this fragrant plant can be used as a food item and you can boil them to make mint tea!

Quick Care

Narrowleaf mountain mint close-up
Narrow leaf mountain mint makes for an amazing easy care ornamental. Source: milesizz
Common Name(s): Narrow-leaf mountain mint; slender mountain mint; common horsemint; Virginia thyme
Scientific NamePycnanthemum tenuifolium
Height & Spread:2-3′ tall and 2-3′ wide
LightFull sun to partial shade
SoilShallow, rocky, well-draining
Water:Low to medium
Pests & Diseases:Virtually free of pests and diseases

The slender mountain mint is part of the mountain mint plant family (Lamiaceae). The narrow-leaf mountain mint has narrow, slender leaves that separate it from other mountain mint species, all of which are native to North America.

This plant is native to every county of central and southern Illinois. It is also found growing in woodland openings, moist thickets and meadows, limestone glades, acid gravel seeps, and abandoned fields.

Pycnanthemum tenuifolium is an erect and tall herb perennial that blooms clusters of tiny, white flowers, has narrow, needle-like foliage and slender, hairless stems. These plants give off a bushy effect thanks to their frequent branching.

It spreads on the ground via rhizomes that allow it to appear as a striking mass of white flowers in late summer. These plants are a favorite among animals and insects – native bees love to swarm the mildly minty fragrant white flowers.

Pycnanthemum tenuifolium Care

Pycnanthemum tenuifolium flowers
Pycnanthemum tenuifolium is a wonderful low-growing ground cover plant. Source: FritzFlohrReynolds

Light & Temperature

It needs full sun, but it can also survive in partially shaded areas. USDA Plant Hardiness Zones 4 to 8 are ideal for this plant, as it is native to regions within these zones. You can stretch it outside these zones with proper care, however.

Water & Humidity

This plant needs a low to medium amount of water. Let the soil dry out completely between watering rounds, or put it on irrigation of some kind.


This mint family plant prefers moist to slightly dry conditions. Tenuifolium Pycnanthemum often grows in rich, loamy, and slightly rocky soil.


This plant has no special fertilizing needs, it’ll grow without additional fertility.


Propagate your plant via divisions and seeds. For division, cut off the tips of your plant in June, divide a clump of your plant in late fall or early spring and use stainless steel pruning shears to divide the shallow root system.

For propagation via seeds, collect the seeds after the first few frosts. If the seeds are ripe, they will fall out when you bend over the stem and shake it. Store these in a sealed, refrigerated container and plant them during the growing season.


To keep your plant from spreading all across your garden, you can occasionally divide it from the roots and either transplant into a new area, or toss into your compost pile.


Pycnanthemum tenuifolium, is a low maintenance plant. However, it can face some growing problems.

Make sure that you don’t over-water your plant or keep it away from sunlight as your plant needs full sun and dry to lightly moist soil to thrive.

Pests & Diseases

This plant is virtually pest-free, and there are no common diseases that affect this plant.


Q. How to tell if my narrow narrow-leaf mountain mint is thirsty for water?

A. The leaves of your plant might develop a yellowish tinge during prolonged periods of drought – this is your sign to water your plant.

Q. Does slender mountain mint smell like mint?

A. The leaves of this plant have a slight minty smell to them and they can be boiled to make mint tea.

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