Hydrangea Section Macrophyllae Cultivars C

'Cap Sizun'

Sterile flowers plentiful, with strikingly serrate sepals, clear pale blue / pale pink, especially attractive when blue; fertile flowers pigmented. Height to 1.2 m; good red leaf colour possible from flowering time onwards. Selected 2006 by Breton breeder Pierre-Michel Kerneur (Pan-Global Plants 2020; Hydrangea Derby 2024; Association Shamrock 2022)

Hydrangea 'Cap Sizun' has strongly serrate sepals, and is especially attractive in blue (Avenue Cottage, Ashprington, Devon, UK; 17 October 2023). Image Julian Sutton.

Autumn tints in Hydrangea 'Cap Sizun' (Avenue Cottage, Ashprington, Devon, UK; 17 October 2023). Image Julian Sutton.

'Chiba Cherry-lips'

An attractive picotee with large white, red-pink edged sepals on the sterile flowers, resembling the classic ‘Kiyosumi-sawa’; young leaves bronze tinted; original plant 1.2 × 1.5 m at maturity. Selected by Crûg Farm Plants, UK, from BSWJ 4817 (Chiba Peninsula, C Honshu, 1997) (Crûg Farm Plants 2024).

Hydrangea serrata 'Chiba Cherry-lips', a selection from wild Japanese seed, is an attractive picotee (private garden, Ayrshire, UK; 24 July 2023). Image Julian Sutton.

China City Series

An extensive Dutch marketing series used in the 1990s by the Kolster nursery (Association Shamrock 2022). We include ‘Nanping’ and ‘Xian’; both went on to be marketed in other series and are still in commerce.

'Chiri-san Sue'

Sterile flowers double, with elongated, mid-blue / pink sepals; about 0.6 × 1.8 m at maturity for the raiser. Collected on Chirisan, southern South Korea, by Dan Hinkley in 1997 under DJHC 970416, and named for his “traveling and soul mate Sue Wynn-Jones [of Crûg Farm]” (Hinkley 2024; Crûg Farm Plants 2024; Hydrangeas Plus 2024).

Hydrangea serrata 'Chiri-san Sue' is a Korean-provenance plant (Windcliff garden, WA, United States; 27 June 2023). Image John Grimshaw.

A single, immensely broad specimen of Hydrangea serrata 'Chiri-san Sue' (Windcliff garden, WA, United States; 27 June 2023). Image John Grimshaw.

Hydrangea serrata 'Chiri-san Sue' has double, delicately pigmented sterile flowers (Windcliff garden, WA, United States; 27 June 2023). Image John Grimshaw.

City-line Series

Dwarf mopheads with large flowerheads in strong colours, stout stems, glossy dark green foliage, and high mildew resistance, introduced from 1997 by German breeder Franz-Xaver Rampp. A major aim was to produce compact potted plants without the use of growth regulators (Hydrangea Derby 2024a). Considered ‘excellent cultivars’ by Church (2007), a few have persisted well in the trade. We describe ‘Rapa’ / ‘Paris Rapa’ (PARIS) and ‘Rabe’ / ‘Berlin Rabe’ (BERLIN). Use of previously published names for some has led to nomenclatural confusion, but ‘real-life’ mistakes in plant identification are unlikely.

'Claudie'

Sterile flowers mauve/pink, not blueing readily, sepals not overlapping; fertile flowers many, a more definite blue / pink. Foliage glossy; stems strong, height to about 1.25 m. A wild find by Corinne Mallet in 1994, on the Izu Peninsula, Honshu; named for cosmonaut Claudie Haigneré, the first Western European woman in space (1996). Protected by US Plant Patent 15,968; marketed in North America by Spring Meadow / Proven Winners, less often grown in Europe. Does not flower well in cold upstate New York. (Boebel 2011; Google Patents 2024; Association Shamrock 2022)

Hydrangea 'Claudie' is a wild-origin H. macrophylla from the Izu Peninsula, Honshu (Arnold Arboretum, MA, United States; 19 July 2024). Image William (Ned) Friedman / Arnold Arboretum. Used under the CC BY-NC 4.0 licence..

Ageing inflorescences of Hydrangea 'Claudie' (Arnold Arboretum, MA, United States; 21 August 2024). Image Kyle Port / Arnold Arboretum. Used under the CC BY-NC 4.0 licence..

'Cof-hm1'

Flowers blue/pink; remontant. A ‘find’ in a Georgia, United States, garden by Michael Dirr in 2015. Claimed as more floriferous and disease resistant than ‘Bailmer’ (ENDLESS SUMMER®) – time and wider experience will tell. Protected by US Plant Patent 32,054, and currently widely marketed in North America. (Dirr 2021; Google Patents 2024)

'Cof-hm2'

Flowers with very thick sepals, green maturing to green with purple and pink streaks and spots, a unique floral effect. Height to about 1.25 m; shiny, dark green foliage. A more or less stabilized shoot selection of ‘Greenmantle’ (apparently an almost forgotten European cultivar, which has these spotted flowers only sporadically – Dirr 2018), developed around 2019 by Michael Dirr and Mark Griffith, Georgia, introduced to the nursery trade about 2022. Protected by US Plant Patent 32,242 (Dirr 2021; Google Patents 2024)

'Cof-hm3'

Flowers blue/pink; remontant. Stems, petioles and veins red; good red/purple autumn leaf colour; height to about 1.8 m. A mophead sport on hardy, remontant ‘Piihm-I’ (TWIST-N-SHOUT®) found in a mass planting in a Connecticut garden by Michael & Bonnie Dirr in 2017. Protected by US Plant Patent 32,584. (Dirr 2021; Google Patents 2024)

'Colonel Durham'

Flowers with entire sepals in globular heads, mauve / clear pink, especially good in its pink state, and ageing red. Height to 1.5 m. An old variety, introduced 1931 by Dutch nurseryman Karl Wezelenburg, but now largely forgotten in Europe. In New Zealand, however, it is a popular plant, rated one of the best pink mopheads by nurseryman and hydrangea enthusiast Glyn Church (Church 2007; Woodleigh Nursery 2024; Association Shamrock 2022). The name presumably commemorates Col. Frank Durham (1872–1947), British gardener, civil engineer, soldier, and one time Secretary of the Royal Horticultural Society.

'Coumont'

(So Long® Series) Flowers tending to light pink, ageing green, in dense, weatherproof heads to 15 cm across; remontant. Height to about 1.2 m. Parentage ‘Santiago’ (serrata × ‘Mariesii Pefecta’) × ‘Blushing Bride’ (‘Veitchii’ × ‘Bailmer’); selected 2010 by Jacques Couturieux, France. Protected by US Plant Patent 31,533 and European Plant Breeders’ Rights (SAPHO 2024; Promesse de Fleurs 2024;Google Patents 2024).

'Crûg Cobalt'

Flowers strong blue on acidic soil; height 1 m at 10 years; foliage ageing purple in sun. By far the most widely grown of a set of four cultivars selected by Crûg Farm Plants, UK, from BSWJ 6241 (Mt Unzen area, Kyushu, Japan, 1998). ‘Crûg Cobalt’ is BSWJ 6241a; the others, described in almost identical terms, are ‘Crûg Bicolor’ (BSWJ 6241c, description emphasising the blue sterile flowers ageing pink), ‘Crûg Caerulean’ (BSWJ 6241d) and ‘Crûg Sō Cool’ (BSWJ 6241b (Crûg Farm Plants 2024).

Hydrangea serrata 'Crûg Cobalt', selected from wild-collected Japanese seed (Crûg Farm, Gwynedd, UK; 17 August 2024). Image Julian Sutton.

Hydrangea serrata 'Crûg Cobalt': older leaves turn purple in sun (private garden, Argyll & Bute, UK; 22 August 2023). Image Julian Sutton.

Hydrangea serrata 'Crûg Cobalt': flowers of different ages make a pretty colour mix (private garden, Argyll & Bute, UK; 22 August 2023). Image Julian Sutton.