Hemp-agrimony.

At a glance

Care level

Easy

Plant type

Perennial herb

Light

Full sun to partial shade

Indoor light

Bright indirect

Water

Every 3 to 7 days

Mature size

1.5 meters

Growth rate

Fast

Hardiness

USDA 4 to 9

Bloom time

Mid summer to early autumn

Care

Keep the soil consistently moist, as this plant naturally thrives in damp areas. Watch for wilting, which is a clear sign it needs more water. It is quite hardy and generally stays healthy without much fuss.

Watering

Water whenever the top inch of soil starts to feel dry to the touch.

Feeding

Apply a balanced organic fertilizer once in early spring to encourage vigorous growth.

Pruning

Cut the stems back to the ground in late winter or early spring before new growth appears.

Repotting

If growing in a container, move to a larger pot every couple of years to prevent it from becoming root bound.

Soil

Moist, fertile, well-draining soil

Soil pH

Neutral to slightly alkaline

Temperature

-20 to 30°C

Humidity

40 to 70%

Safety

People

The plant contains pyrrolizidine alkaloids which can cause liver damage if ingested.

Pets

This plant is considered toxic to cats and dogs if ingested.

Children

Keep this plant away from children as ingestion of any part can cause illness.

Contact allergens

Handling the foliage may cause mild skin irritation in sensitive individuals.

Airborne allergens

The abundant pollen can trigger allergic reactions in those sensitive to Asteraceae pollen.

Edibility

This plant is considered toxic and should not be consumed by humans or pets.

How to identify it

• Opposite, palmate, three-lobed leaves
• Clusters of fuzzy, pinkish flowers
• Stems often have reddish purple spots
• Tall, upright, branching growth habit

Height

1 to 1.5m

Spread

0.6 to 0.9m

Leaves

dark green, deciduous

Flowers

pink, pale purple, 0.5 to 1cm

Fruit

brown, Autumn

Problems to watch for

• AphidsCommon
• Powdery MildewCommon
• Leaf SpotUncommon
• Slugs and SnailsUncommon

Growing it

Propagation

division, seed, cuttings

When to plant

spring, autumn

Plant this in a moisture-retentive spot where it can act as a focal point for late-season pollinators.

Grows well with

• Purple Loosestrife · They share a love for damp soil and look beautiful together in a meadow setting.
• Meadowsweet · This plant thrives in the same wet conditions and provides a nice textural contrast.

Similar species

• Joe Pye Weed · It is a close relative with similar flower colors and a preference for moist habitats.

Science

Family

Asteraceae

Genus

Eupatorium

Order

Asterales

Class

Magnoliopsida

Native range

Europe, Western Asia, and Northern Africa.

Conservation

It is common and widespread throughout its native range and is not currently threatened.

It naturally colonizes damp meadows and woodland edges where it provides essential late-season nectar for insects.

Value to wildlife

nectar source, larval host plant

Pollinators

bees, butterflies, moths

Uses

pollinator gardens, wildlife meadows, damp borders

Taxonomy resolved against GBIF.

Questions people ask

Does it need a lot of water?

Yes, it prefers consistently moist soil and will struggle in dry conditions.

Can I grow it in a container?

It is best suited for the ground, but can grow in a large pot if kept very moist.

Where the name comes from

The name Eupatorium honors Mithridates Eupator, an ancient king who supposedly discovered medicinal uses for the genus. Cannabinum refers to the leaves which look like those of hemp.

Good to know

• It is commonly known as hemp-agrimony due to the leaf shape resembling hemp.
• The flowers have a faint, pleasant vanilla scent.
• It thrives in damp soil and is often found near streams or in marshy areas.

Also in

• Plants toxic to cats and dogs