Difference between revisions of "Hydrangea"

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| high =    <!--- 3ft (1m) -->
 
| high =    <!--- 3ft (1m) -->
 
| wide =    <!--- 20in (65cm) -->
 
| wide =    <!--- 20in (65cm) -->
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| origin =     <!--- Mexico, S America, S Europe, garden, etc -->
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| origin = S&E Asia, N&S America
 
| poisonous = mildly toxic
 
| poisonous = mildly toxic
 
| lifespan = perennial
 
| lifespan = perennial
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| genus = Hydrangea
 
| genus = Hydrangea
 
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'''''Hydrangea''''' ({{pronEng|haɪˈdreɪndʒ(i)ə}}, common names '''Hydrangea''' and '''Hortensia''') is a genus of about 70-75 species of [[flowering plant]]s native to southern and eastern [[Asia]] (from [[Japan]] to [[China]], the [[Himalaya]] and [[Indonesia]]) and [[North America|North]] and [[South America]]. The flowers are extremely common in the [[Azores]] Islands of [[Portugal]], particularly on [[Faial Island]], which is known as the "blue island" due to the vast number of hydrangeas present on the island. By far the greatest species diversity is in eastern Asia, notably China and Japan (See: Japanese [[Ajisai flower]]). Most are [[shrub]]s 1-3 m tall, but some are small [[tree]]s, and others [[liana]]s reaching up to 30 m by climbing up trees. They can be either [[deciduous]] or [[evergreen]], though the widely cultivated temperate species are all deciduous.
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'''''Hydrangea''''' is a genus of about 70-75 species of [[flowering plant]]s. By far the greatest species diversity is in eastern Asia, notably China and Japan (See: Japanese [[Ajisai flower]]). Most are [[shrub]]s 1-3 m tall, but some are small [[tree]]s, and others [[liana]]s reaching up to 30 m by climbing up trees. They can be either [[deciduous]] or [[evergreen]], though the widely cultivated temperate species are all deciduous.
  
 
Hydrangea [[flower]]s are produced from early [[Spring (season)|spring]] to late [[autumn]]; they grow in flowerheads ([[corymb]]s or [[panicle]]s) at the ends of the stems. In many species, the flowerheads contain two types of flowers, small fertile flowers in the middle of the flowerhead, and large, sterile bract-like flowers in a ring around the edge of each flowerhead. Other species have all the flowers fertile and of the same size.
 
Hydrangea [[flower]]s are produced from early [[Spring (season)|spring]] to late [[autumn]]; they grow in flowerheads ([[corymb]]s or [[panicle]]s) at the ends of the stems. In many species, the flowerheads contain two types of flowers, small fertile flowers in the middle of the flowerhead, and large, sterile bract-like flowers in a ring around the edge of each flowerhead. Other species have all the flowers fertile and of the same size.
  
 
In most species the flowers are [[white]], but in some species (notably ''H. macrophylla''), can be blue, red, pink, or purple. In these species the exact colour often depends on the [[pH]] of the soil; [[acid]]ic soils produce blue flowers, neutral soils produce very pale cream petals, and [[alkaline]] soils results in pink or purple. Hydrangeas are one of very few plants that accumulate [[aluminium]]. Aluminium is released from acidic soils, and in some species, forms complexes in the hydrangea flower giving them their blue colour.  
 
In most species the flowers are [[white]], but in some species (notably ''H. macrophylla''), can be blue, red, pink, or purple. In these species the exact colour often depends on the [[pH]] of the soil; [[acid]]ic soils produce blue flowers, neutral soils produce very pale cream petals, and [[alkaline]] soils results in pink or purple. Hydrangeas are one of very few plants that accumulate [[aluminium]]. Aluminium is released from acidic soils, and in some species, forms complexes in the hydrangea flower giving them their blue colour.  
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Hydrangeas are moderately toxic if eaten, with all parts of the plant containing [[cyanogenic glycoside]]s. However, poisoning is rare, as the plant does not look like an enticing food source.
  
 
Species in the related genus ''[[Schizophragma]]'', also in Hydrangeaceae, are also often known as hydrangeas. ''[[Schizophragma hydrangeoides]]'' and ''[[Hydrangea petiolaris]]'' are both commonly known as climbing hydrangeas.
 
Species in the related genus ''[[Schizophragma]]'', also in Hydrangeaceae, are also often known as hydrangeas. ''[[Schizophragma hydrangeoides]]'' and ''[[Hydrangea petiolaris]]'' are both commonly known as climbing hydrangeas.
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Hydrangeas are moderately toxic if eaten, with all parts of the plant containing [[cyanogenic glycoside]]s. However, poisoning is rare, as the plant does not look like an enticing food source.
 
  
 
==Cultivation==
 
==Cultivation==

Revision as of 21:19, 25 January 2009


Hydrangea macrophylla


Plant Characteristics
Lifespan: ⌛ perennial
Origin: ✈ S&E Asia, N&S America
Poisonous: ☠ mildly toxic
Cultivation
Scientific Names

Hydrangeaceae >

Hydrangea >


Hydrangea is a genus of about 70-75 species of flowering plants. By far the greatest species diversity is in eastern Asia, notably China and Japan (See: Japanese Ajisai flower). Most are shrubs 1-3 m tall, but some are small trees, and others lianas reaching up to 30 m by climbing up trees. They can be either deciduous or evergreen, though the widely cultivated temperate species are all deciduous.

Hydrangea flowers are produced from early spring to late autumn; they grow in flowerheads (corymbs or panicles) at the ends of the stems. In many species, the flowerheads contain two types of flowers, small fertile flowers in the middle of the flowerhead, and large, sterile bract-like flowers in a ring around the edge of each flowerhead. Other species have all the flowers fertile and of the same size.

In most species the flowers are white, but in some species (notably H. macrophylla), can be blue, red, pink, or purple. In these species the exact colour often depends on the pH of the soil; acidic soils produce blue flowers, neutral soils produce very pale cream petals, and alkaline soils results in pink or purple. Hydrangeas are one of very few plants that accumulate aluminium. Aluminium is released from acidic soils, and in some species, forms complexes in the hydrangea flower giving them their blue colour.

Hydrangeas are moderately toxic if eaten, with all parts of the plant containing cyanogenic glycosides. However, poisoning is rare, as the plant does not look like an enticing food source.

Species in the related genus Schizophragma, also in Hydrangeaceae, are also often known as hydrangeas. Schizophragma hydrangeoides and Hydrangea petiolaris are both commonly known as climbing hydrangeas.

Cultivation

Hydrangea calendar?
January:
February:
March:
April:
May:
June:
July:
August:
September:
October:
November:
December:
Notes:

Hydrangeas are popular ornamental plants, grown for their large flowerheads, with Hydrangea macrophylla being by far the most widely grown with over 600 named cultivars, many selected to have only large sterile flowers in the flowerheads. Some are best pruned on an annual basis when the new leaf buds begin to appear. If not pruned regularly, the bush will become very 'leggy', growing upwards until the weight of the stems is greater than their strength, at which point the stems will sag down to the ground and possibly break. Other species only flower on 'old wood'. Thus new wood resulting from pruning will not produce flowers until the following season.

Propagation

Pests and diseases

  • BACTERIAL DISEASES - Bacterial blight (Pseudomonas solanacearum), Bacterial leaf spot (Pseudomonas cichorii)
  • FUNGAL DISEASES - Bud and flower blight, (Botrytis cinerea), Interveinal chlorosisn (Lack of iron uptake due to alkaline soils), Fungal leaf spots (Cercospora hydrangeae), (Corynespora cassicola), (Phyllosticta hydrangeae), (Septoria hydrangeae), Powdery mildew (Erysiphe polygoni), Root rot (Pythium spp.), Rust (Pucciniastrum hydrangeae), Southern blight (Sclerotium rolfsii), (teleomorph: Athelia rolfsii (Curzi) Tu & Kimbrough)
  • VIRAL DISEASES - Phyllody (Hydrangea ringspot virus), Ringspots (Hydrangea ringspot virus), (Tobacco ringspot virus), (Tomato spotted wilt virus), (Tomato ringspot virus)

Species

Partial list of species:

Hydrangea sp, fertile individual flower.
Hydrangea, flowers in winter.
H. macrophylla, Watermouth Castle, north Devon, England
closeup of petals
Hydrangeas in front of the Office de Tourisme Building in Chartres, France.

Gallery

  • Hydrangea macrophylla, flowers.

  • Hydrangea macrophylla, flowers

  • Hydrangea sp. painted by the botanical artist Redouté

  • Hydrangea quercifolia

  • Hydrangea macrophylla, leaves

  • Wild Hydrangea v. Annabelle
    Hydrangea arborescens

  • Wild Hydrangea v. Annabelle
    Hydrangea arborescens

  • Hydrangea aspera ssp. sargentiana

References

External links

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