Though hostas are native to Japan, China, and Korea, the majority of species come from Japan. This article is the seventh in a series which will talk about those species. Previous articles have covered Hosta alismifolia, H. nakaiana, H. pycnophylla, H. longipes, H. longissima, and H. montana. If you missed any of the past articles, you can find them on my blog site: https://thecottagegardener53012.wordpress.com.
Today we will discuss H. kikutii, Hyuga Giboshi, which is translated from the Japanese as “Hosta from Hyuga.”
Hosta kikutii is one of the five most common hosta species in Japan. The others are H. longipes, H. montana, H. rectifolia, and H. sieboldii. The native range extends approximately 600 miles. Because it inhabits a wide range of environments, much variation exists within the population, resulting in several named varieties and forms. In the southern part of its range it is sometimes called by the Japanese name that translates to “Hosta growing in Sunny Places,” because that is where it is found. In other places it is found growing in ravines and in cracks of rocks. Hosta kikutii exhibits a rapid growth rate, making it a fine specimen for most gardens. The name kikutii honors Akio Kikuchi (1883-1951), the Japanese botanist who did much of the early research on this species.
The typical variety is referred to as H. kikutii var. kikutii, and is found primarily in Western Kyushu, mostly in river valleys and on wet rocks. Leaves are lightly rippled, elongated, and lance shaped. Height is up to about 16 inches. The backs of the leaves are shiny, often with a whitish cast. Flowering is late, usually from late August into mid-September. Flowering scapes have large, leaf-like bracts that start out green and change to white. Scape height is about 26 inches. A key identification characteristic of the species is the pointed flower bud that somewhat resembles the beak of a crane. Flowers are usually a light lavender color, though at lower elevations it leans toward white. Hosta kikutii is known for its clustered flowers at the tip of the scape. Mark Zilis has observed up to 80 flowers in the top 4 1/2 inches of the scape. The plant is fertile and produces many seed pods.
A variation of H. kikutii var. kikutii is the form leuconota (Urajiro Hyuga giboshi.) Leaves of this plant are whitish-backed and it has near-white flowers in September. This form was once known as H. kikutii ‘Pruinosa’ and H. kikutii ‘Urajiro.’
Hosta kikutii var. yakusimensis (Hime Hyuga giboshi) is found primarily in Southern Kyushu and Yakushima Island. It has slightly rippled narrow leaves and pale lavender flowers. Leaf width is about 1/3 the length. Hosta kikutii var. tosana (Tosa-no giboshi) is known for its shiny oval leaves. The width of its leaves is about 1/2 the length. Hosta kikutii var. polyneuron (Sudare giboshi) is found in the Satsunan Islands region of Japan. Leaves are oval, but may exhibit either smooth or rough undersides. Flowers are light purple.
Hosta kikutii var. caput-avis (Unazuki giboshi) is found in West-central Shikoku. There are two different forms of this variety, one of which is dwarf. The typical form grows to a dense 19 inch mound. The dwarf form tops out at 8 inches and is found in Mie Prefecture. Flowering scapes hang either horizontally to the ground or downward. This characteristic makes variety caput-avis ideal for growing on hillsides or at the edges of walls. The dwarf form, known as Ko unazuki giboshi, is somewhat rare in cultivation.
Many sports of Hosta kikutii have been found in Japan. They may be white streaked, gold streaked, gold centered, or white margined. Some examples: ‘Kifukurin Hyuga,’ sometimes referred to as ‘Kifukurin’ or ‘Albomarginata,’ has a dark green leaf center with a greenish-yellow margin. ‘Kishiro-nakafu Hyuga’ has a yellow center and green margin. ‘Yoshinogawa’ is a H. kikutii var. polyneuron sport with green and white streaked leaves. An interesting sport is ‘Katsuragawa Beni’ which was found on Shikoku Island. It has red petioles, a characteristic that is rather unusual in the species.
Some of the interesting hybrids that have been introduced include the following. As you can see, various species have been crossed with H. kikutii, but primarily green-leaved plants have been obtained:
‘Fatal Attraction’ – (‘Dorset Clown’ x kikutii) Green with a creamy edge.
‘Glacier Cascade’ – (kikutii x hypoleuca) Lance-shaped green leaves with a white back.
‘Harvest Delight’ – A plant that exhibits characteristics typical of the species, but was crossed with H. longipes f. hypoglauca to obtain ‘Red October.’
‘Harvest Desire’ – (H. longipes x H. kikutii) Shiny green lightly rippled and cupped leaves
‘Hillbilly Blues’ – (‘Hirao 59’ x ‘Hadspen Blue’) A plant that has both H. sieboldiana and H. kikutii blood on it. As you can guess from the name, it is one of Tony Avent’s introductions!
‘Roy’s Pink’ – (H. kikutii x H. rupifraga) Medium green leaves with pinkish flowers
‘Stingray’ – (H. kikutii x H. montana) Green leaves with a heavily rippled margin.
‘Summer Dress’ – (‘August Moon’ x H. kikutii) Greenish-yellow changing to golden-yellow leaves. Wavy margin. Scapes top out at 6 feet.
A number of sports of H. kikutii var. caput-avis have also been found in the wild. ‘Fuiri Unazuki’ has a white margin and green center. ‘Kinokawa Unazuki’ has mottled foliage. ‘Kishira-nakafu Unazuki’ has leaves with a light green center and dark green margin. ‘Kishiro-shimafu Unazuki’ leaves are creamy-yellow streaked.
Seedlings of H. kikutii var. caput-avis include:
‘Green Fountain’ – Large mound of cascading long wavy green foliage.
‘Incoming’ – An open pollinated seedling with dark green wavy, corrugated leaves. Flower petiole is purple.
‘Koyurugi’ – (H. hypoleuca x H. kikutii var. caput-avis) Chartreuse with green streaks
‘Red Neck Heaven’ – Another creative name by Tony Avent! Leaves are white-backed. White flowers and a red petiole.
‘Tristesse’ (H. kikutii caput-avis x H. pycnophylla) Rippled margin and a twisted tip
‘Uncle Albert’ (H. hypoleuca x H. kikutii caput-avis) Glossy, cupped leaves with a white back. Dark purple spotted scape.
When you look at the myHostas database you can see that Hosta kikutii has not been used as much as many other Japanese species in hybridizing. But this variable species is full of desirable characteristics: Ease of growth, fertile, lance-shaped leaves, glossy, small to medium size, horizontal scapes, late bloom, etc. It makes a great plant on its own, but can contribute much to a breeding program. Sometimes greatness can be achieved from the common.
Hosta kikutii var. yakusimensis
The Cottage Gardener 