''Hydrangea aspera'' is a species of flowering plant in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Hydrangeaceae Hydrangeaceae is a family of flowering plants in the order Cornales, with a wide distribution in Asia and North America, and locally in southeastern Europe. Description The genera are characterised by leaves in opposite pairs (rarely whorled or ...

native to dense forests in the region between the Himalayas, across southern China, to Taiwan. It is a large, erect

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

growing to tall and wide, with broadly oval leaves and dense branches. The flowers are typically borne in large flat heads in late summer, and are in variable shades of pale blue and pink, fringed by white or pale pink sterile

florets This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

. The Latin ''aspera'' means "rough-textured" and refers to the downy lower surface of the leaves. Due to how highly cultivated ''Hydrangea aspera'' is, coupled with the extensive species range, the related taxonomy of subspecies and potential synonyms is uncertain.

Anatomy and Characteristics

''Hydrangea aspera'' has lace capped, flat-topped

inflorescences In botany, an inflorescence is a group or cluster of flowers arranged on a plant's stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a main axis ( pe ...

with flowers that vary in color based on the pH level of the soil. The sterile flowers of this species have longer

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

than those of the fertile flowers. Plants that grow in more acidic soil have flowers that are various shades of blue. The lower the pH level is, the more vibrant or pigmented the blue color appears. At higher or more alkaline pH levels, the flowers are various shades of pink. In addition to the pH level of the soil, the amount of soluble aluminum available in the soil also effects the flower color. When a plant is able to absorb more aluminum ions, the flower color is found to be more blue. The coarse texture of the leaves of ''Hydrangea aspera'' is one of the key characteristics that differentiates this species from the

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of ''Hydrangea aspera'', as well as the other species under the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Hydrangea ''Hydrangea'' ( or ) is a genus of more than 70 species of Flowering plant, flowering plants native plant, native to Asia and the Americas. Hydrangea is also used as the common name for the genus; some (particularly ''Hydrangea macrophylla, H. m ...

''. The shape, size, and lower leaf texture of this species varies slightly depending on the exact region where it is naturally found. Also published as:

Cultivation

The plant is widely cultivated, and favors a sheltered position in acidic or neutral soil, with best growth often in partial or afternoon shade. The leaves, in some forms exceeding 30.5 cm (12 inches) long, are vulnerable to drying winds as well as physical wind damage. Numerous

cultivars A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue cult ...

have been produced as ornamental subjects for parks and gardens. They include: * 'Anthony Bullivent' * 'Longipes' * 'Mauvette' * 'Peter Chappell' * 'The Ditch' In addition to forms of garden origin, various forms of wild origin are cultivated such as ''Kawakamii'', ''Macrophylla'', ''Robusta'', ''Sargentiana'', ''Strigosa'', and ''Villosa''. The phenotype for plant images returned by a web search on such terms can vary widely, a sign of unsettled taxonomy or complex expression of forms due to wide geographic ranges or other factors. Some authorities give full species status, e. g. ''H. robusta'' and ''H. longipes'', whereas other sources assign subspecies, e.g. ''H. aspera ssp. robusta'', or ''H. aspera ssp. kawakamii''. Most researchers and

horticulturalists Horticulture (from ) is the art and science of growing fruits, vegetables, flowers, trees, shrubs and ornamental plants. Horticulture is commonly associated with the more professional and technical aspects of plant cultivation on a smaller and mo ...

agree that further study is needed to solidify the

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

, as there is an insufficient amount of data published. This is especially relevant in respect to the viability of hybrids, whether or not hybrids are sterile, and the chromosomal differences between the aforementioned groups, as further data in these sectors could significantly assist with distinguishing the species and subspecies. The cultivar ''H. aspera'' 'Macrophylla' (not to be confused with '' H. macrophylla'') has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

References

aspera Plants described in 1825 {{Cornales-stub