Hydrangea macrophylla 

(hii-drain' gee-ah ma-crow-phil' ah)

Common name: Florist's Hydrangea, Snowball Plant

Family: Saxifragaceae, Saxifrage

Height x width: 1'x1-2' indoors in pots, 3-5' x 3-5' outdoors in zones 6-9

Foliage: large 4-8" long and 3-6" wide, broadly ovate, coarsely toothed, often shiny

Flowers: large clusters (corymbs, umbels) terminal and axillary, 6-9" wide flat ("Lacecap" type) or mound ("Mophead" or "Snowball" or "Hortensia" type--the more traditional form and more commonly seen); generally blue, pink, red, white, purplish sepals--flowers themselves are greenish, small and insignificant; a few sterile flowers with many fertile flowers, Lacecap types have a row of sterile flowers around a cluster of fertile ones; on woody stems

Light: bright

Temperature: cool indoors, tolerates heat in shade in warm climates outdoors

Watering: keep well watered, don't allow to dry

Humidity: average

Soil: well-drained

Pests and Problems: aphids, spider mites, scales; leaf scorch (brown edges) from dry air or drafts, or root damage from high salts and dry soil

Growth habit, uses: flowering potted plant; flowering shrub in zones 6-9

Other interest: native to Japan, China and Southeast Asia; an old-fashioned plant popular in Victorian times;

Other culture: plants bloom on two-year wood which should be considered in pruning; after bloom maintain as a shrub, placing outdoors with pot sunk in ground in summer; bring indoors when leaves fall and keep cool but above freezing; gradually bring into warmth in late winter for summer bloom; forced commercially primarily for Easter through Mother's Day; flower buds develop at 60-65ºF after 6 weeks of total darkness at 40-45ºF, or after overwintering outdoors where hardy; on pink-blue varieties, blue flowers develop with acidic soil pH (5.0, as from aluminum sulphate), pink flowers from alkaline soil pH (6.5, as from lime).

Propagation: stem or tip cuttings

Cultivars:

There is some taxonomic disagreement whether some Lacecap types are actually in serrata or whether this is a subspecies of macrophylla; other Lacecap types are in macrophylla. Those listed below are only a few of the most representative, worthy and available of the 100 or so in commerce.
 
Cultivar flower color, size other
'Bluebird' blue, lacecap  
'Blue Wave' blue, lacecap  
'Bottstein' red-rose, medium short
'Fire Light' ('Leuchtfeuer') dark pink, large tall
'Jennifer' red, small medium height
'Kuhnert' light blue, medium medium height
'Lanarth White' white, lacecap  
'Lilacina' pink to blue, lacecap  
'Masja' red-pink, large tall
'Mathilda Gutches' blue, medium medium tall, European
'Merritt Supreme' medium pink, large short, popular commercially
'Nikko Blue' pink to bright blue most popular and available
'Pink Beauty' pink  
'Pink Lacecap' pink, lacecap  
'Rose Supreme' light pink, very large very tall, popular
'Sara' light pink  
'Sister Therese' white, large short
'Tricolor' pink to blue leaves mottled cream, yellow
'Veitchii' white fading pink leaves dark green
'White Wave' pink/blue, white outer  


©Authored by Dr. Leonard Perry, Professor, University of Vermont as part of PSS121, Indoor Plants.

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