H. ‘Sea Monster’

Hosta ‘Sea Monster’ is a registered cultivar (1978) .

Year registered	1978
Section class	I-1 (Giant)

Overview

Registered in 1978, 'Sea Monster' is a giant blue-green hosta cultivar of unknown parentage. It is visually distinctive for its heavily corrugated, nearly round leaves with medium green margins, a moderate glaucous bloom on the undersides, and a cordate base.

In the Garden

This cultivar reaches 24 inches (61.0 cm) in height and spreads to 46 inches (116.8 cm) in diameter, making it suitable as a bold specimen or focal point in shaded borders and woodland gardens. It performs best in partial to full shade, where its blue-green foliage retains its color, and pairs well with ferns, astilbes, and other shade-tolerant perennials. Its substantial size and corrugated texture also provide strong contrast alongside finer-textured plants.

Care Notes

Provide consistent moisture, especially during dry periods, and apply a balanced fertilizer in early spring as new growth emerges. Slugs and deer may damage the foliage, so monitoring and appropriate controls are recommended in typical hosta-growing zones.

Size and leaf

Clump height	24 in (61 cm)
Clump width	46 in (116.8 cm)
Leaf length	14 in (35.6 cm)
Leaf width	12.75 in (32.4 cm)
Vein pairs	18
Leaf	moderate glaucous bloom underneath; heavily corrugated, moderately wavy
Flower scape height	29–36 in (73.7–91.4 cm)

From the American Hosta Society Registry record.

Parentage

Registered cultivars that list Hosta ‘Sea Monster’ as a parent:

H. ‘Lakeside Main Man’ (seedling (pollen parent))
H. ‘Lochness’ (seedling (pod parent))
H. ‘Monster Babe’ (seedling (pod parent))
H. ‘Swamp Monster’ (seedling (pod parent))
H. ‘Timeless Treasure’ (seedling (pod parent))

Similar cultivars

Other registered hostas in the same AHS section class (I-1, giant size):

Related guides

Registration data: AHS Registry #5008