purple giant hyssop

(Agastache scrophulariifolia)

Conservation Status

IUCN Red List

not listed

NatureServe

NNR - Unranked

SNR - Unranked

Minnesota

not listed

 
purple giant hyssop
Photo by Greg Watson
 
Description

Purple giant hyssop is a 36 to 60 tall, erect, late-flowering perennial forb that rises from a rhizome.

The stems are erect, obtusely 4-angled, diamond-shaped in cross section, and branched above the middle. They are usually tinged purple. They have a sparse to dense covering of short, soft, downward-curved hairs along the ridges.

The leaves are opposite, mostly thin, egg-shaped to oblong egg-shaped, 2 to 5 long, and up to 2 wide. Lower leaves are on leaf stalks up to 2 long. The leaf stalks are usually covered with short, soft hairs, sometimes covered with long, soft, shaggy, unmatted hairs. The leaves become only slightly smaller and the leaf stalks only slightly shorter as they ascend the stem. Lower leaf blades are rounded to almost heart-shaped at the base and tapered to a point at the tip with straight or concave sides along the tip. Upper leaf blades are tapered at the base. The upper leaf surface is green and either hairless or covered with short, soft hairs. The lower surface is green, not white, and may be hairless or covered with long, soft, shaggy, unmatted hairs. The margins are coarsely toothed with sharp, forward-pointing teeth. The leaves emit a strong, anise-like odor when crushed.

The inflorescence is a dense spike at the end of the stems and branches. The spikes are usually continuous, sometimes interrupted, up to 6 long, and to ¾ wide, including the corollas. The flowers are arranged in dense whorls that are subtended by hairless, broadly egg-shaped, abruptly tapered, inconspicuous bracts.

The individual flowers are about ½ long. There are 5 green sepals fused onto a ¼ to long calyx tube with 5 lance-shaped or triangular lobes. The calyx is hairless. There are 5 petals fused into a funnel-shaped corolla tube with a 2-lobed upper lip and a 3-lobed lower lip. The corolla is often white, sometimes pale pink to purple, and extends well beyond the calyx. There are 4 stamens with purple anthers that protrude well beyond the corolla. The sepals that remain on the spike after the corollas have dropped off are green or whitish, not purple.

The fruit is a more or less 3-sided nutlet.

 

Height

36 to 60

 

Flower Color

White or pale pink to purple

 

Similar Species

Blue giant hyssop (Agastache foeniculum) is a much shorter plant, reaching only 36 in height at maturity. The underside of the leaf is whitish due to a covering of microscopic white hairs. The flowers are blue. The sepals that remain on the spike after the corollas have dropped off are purple.

Habitat

Dry. Upland woods and thickets. Partial sunlight.

Ecology

Flowering

August to September

 

Pests and Diseases

 

Use

 

Distribution

Distribution Map

 

Sources

2, 3, 4, 5, 7, 8, 22, 24, 28, 29, 30.

9/4/2024    
     

Nativity

Native

     

Occurrence

 

Taxonomy

Kingdom

Plantae (green algae and land plants)

Subkingdom

Viridiplantae (green plants)

Infrakingdom

Streptophyta (land plants and green algae)

Superdivision

Embryophyta (land plants)

Division

Tracheophyta (vascular plants)

Subdivision

Spermatophytina (seed plants) / Angiospermae (flowering plants)

Class

Magnoliopsida (flowering plants)

Superorder

Asteranae

Order

Lamiales (mints, plantains, olives, and allies)

Family

Lamiaceae (mint)

Subfamily

Nepetoideae

Tribe

Mentheae

Subtribe

Nepetinae (catmints, ground ivies, and hyssops)

Genus

Agastache (hyssops)

   

Subordinate Taxa

 

   

Synonyms

Agastache scrophulariifolia var. mollis

Lophanthus scrophulariaefolius

   

Common Names

figwort giant-hyssop

purple giant hyssop

purple giant-hyssop

 

 

 

 

 

 

 

 

 

Glossary

Bract

Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.

 

Calyx

The group of outer floral leaves (sepals) below the petals, occasionally forming a tube.

 

Corolla

A collective name for all of the petals of a flower.

 

Rhizome

A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.

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Greg Watson

purple giant hyssop

Purple Giant Hyssop flowering on the trail.

MinnesotaSeasons.com Photos
purple giant hyssop   purple giant hyssop

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Plant 27
Derelict Drifter

About

Published on Aug 20, 2012

This looks like it may be a Agastache scrophulariifolia. I'm not sure though.

 

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Greg Watson
5/27/2022

Location: Root River State Trail - Lanesboro to Whalan

Purple Giant Hyssop flowering on the trail.

purple giant hyssop
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