blue giant hyssop

(Agastache foeniculum)

Conservation Status
blue giant hyssop
 
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

SNR - Unranked

     
  Minnesota

not listed

     
           
           
           
           
           
           
 
Description
 
 

Blue giant hyssop is a 24 to 36 tall, erect, perennial forb that rises from a taproot.

The stems are erect, square, and occasionally branched above the middle. They are usually hairless, sometimes slightly hairy.

The leaves are opposite, egg-shaped to triangular egg-shaped or rhombic egg-shaped, up to 3½ long, and up to 2 wide. They are on leaf stalks that are no more than long. The leaf blades are broadly angled or squared off at the base and tapered to a point at the tip with straight or concave sides along the tip. The upper leaf surface is dull green and hairless. The lower surface is whitish due to a dense covering of microscopic, fine hairs. The hairs are barely discernible when using a hand lens with 10x magnification. 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 up to 6 long, ¾ to 1 wide including the corollas, and are often interrupted at the base. 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 dull blue-violet sepals fused onto a ¼ to long calyx tube with 5 lance triangular-shaped lobes. The calyx tube is minutely hairy when in flower. 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 blue and extends well beyond the calyx. There are 4 stamens with purple anthers that protrude well beyond the corolla. After the corollas drop off, the spike that remains is blue-violet, not green or whitish. There is no floral scent.

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

 
     
 

Height

 
 

24 to 36

 
     
 

Flower Color

 
 

Blue

 
     
 

Similar Species

 
 

Purple giant hyssop (Agastache scrophulariifolia) is a much taller plant, 36 to 60 in height at maturity. The underside of the leaves are green, not white. The calyx is green and hairless. The individual flowers are white or pale pink to purple. The spike that remains after the flowers have dropped is green or whitish, not purple.

 
     
 
Habitat
 
 

Dry to moderate moisture. Upland woods and prairies. Full or partial sun.

 
     
 
Ecology
 
 

Flowering

 
 

July to August

 
     
 

Pests and Diseases

 
 

 

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 28, 29, 30.

 
  2/22/2023      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Common

 
         
 
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)  
  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)  
       
 

Synonyms

 
  Agastache anethiodora  
       
 

Common Names

 
 

anise hyssop

anise-mint

blue giant hyssop

blue giant-hyssop

fragrant giant hyssop

lavender giant hyssop

licorice-mint

 

 

 

 

 

 

 

 

 

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.

 
 
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Leaves

 
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