plant of the month
Hydrangea spp. (hy-DRAN-jee-uh, hy-DRAN-juh)
H. macrophylla: hortensia, mophead hortensia, lacecap hortensia, garden Hydrangea, big-leaf Hydrangea, French Hydrangea
H. paniculata: panicle Hydrangea, peegee Hydrangea
Hydrangeas are shrublike plants with small star-shaped florets that form either large rounded heads (H. macrophylla) or pyramidal heads (H. paniculata).
The rounded flower heads are either “mopheads,” with densely massed sterile florets, or “lacecaps,” with a ring of sterile florets surrounding tiny fertile flowers.
Leaves are large and dark green, with roughly serrated edges.
Hydrangeas, particularly the mopheads, are available in whites; pinks; violets (red-violet, blue-violet, lavender, purple); blues; greens; and even reddish-wines and browns, as well as bicolors and multicolors.
Some Hydrangea flower colors are determined by the acidity or alkalinity of the soil: blue if grown in acidic soil and pink if grown in alkaline soil. White Hydrangeas are not changed by soil type.
New varieties are continuously being genetically engineered to create specific colors, and these are not changed by soil. Growers also use spray dyes to alter Hydrangeas hues, so the color range of these flowers is virtually limitless
Indoors, Hydrangea plants usually bloom up to four weeks, with each flower head lasting 15 to 20 days, depending on light, temperature and care.
These plants are readily available from February through May, but they can be purchased year-round in many areas, depending on grower.
outdoor and consumer care
LIGHT Potted Hydrangeas require bright light but no exposure to direct sun.
WATER Hydrangeas are thirsty plants. Keep potting medium moist at all times to prevent wilting, which will reduce longevity. Water these plants with room-temperature rainwater or soft water. If the potting medium dries out, submerge the pots in water until completely saturated (approximately 1 hour), then allow them to drain. Do not allow pots to sit in water, or root rot may result.
TEMPERATURE Hydrangeas prefer cool temperatures—60 F to 70 F during the day and 50 F to 60 F at night.
HUMIDITY Mist the leaves occasionally.
ETHYLENE SENSITIVITY Hydrangeas are moderately sensitive to ethylene and may exhibit flower-shattering when exposed to the gas. Check with your supplier to make sure your plants are treated with an anti-ethylene agent at the grower or transportation level, and keep them away from sources of ethylene in your facilities, especially produce.
FERTILIZER As houseplants, Hydrangeas generally do not require fertilizer.
GROWING MEDIUM Hydrangeas are usually planted in a mixture of peat or Sphagnum moss and potting soil.
PESTS Aphids and spider mites are common pests, and in some areas, snails and slugs can be problems. Control aphids and spider mites by washing the plants with an insecticidal soap, and remove snails and slugs by hand.
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If large amounts of Hydrangea bark, leaves or flower buds are ingested, nausea, stomach pain, vomiting and sweating can occur. Advise customers to keep these plants out of reach of children and pets.
WHAT’S IN A NAME The name “Hydrangea” comes from the Greek roots hydro/hydra (water) and angos/aggos/angeon (jar or vessel). The names refer to the plant’s requirement for lots of water and to its seed capsules, which the ancient Greeks thought resembled cups.
The specific epithet “macrophylla” (mak-row-FILL-uh) means large-leafed.
FAMILY Formerly included in the Saxifragaceae (saxifrage) family, Hydrangeas have been reclassified into the Hydrangeaceae family. A close relative is mock orange (Philadelphus).
HOME SWEET HOME Hydrangeas are native primarily to Japan, but some species also are native to Korea and northeastern China as well as the temperate regions of North and South America.
(See more Hydrangea “Fun Facts” in “Cut Flower of the Month,” Page 20.)
Photos: Bay City Flower Company, Inc.
Some information provided by:
Botanica, by R.J. Turner Jr. and Ernie Wasson
Chain of Life Network® , www.chainoflifenetwork.org
Houseplant Encyclopedia, The
by Ingrid Jantra and Ursula Krüger
House Plant Expert, The, by Dr. D.G. Hessayon
SAF Flower & Plant Care
by Terrill A. Nell, Ph.D., and Michael S. Reid, Ph.D.