H: Symbol for hydrogen, an essential element.
H2Optimara: Trademark given to self-watering devices developed by Optimara. See MiniWell, MaxiWell, Watermaid and WaterShip.
Habit: See Growth Habit.
Haiti: Optimara variety. Medium, standard African Violet (4-inch pot size) with single, bi-color flowers. Flowers are purple with a white edge. Leaves are medium green (red reverse). Introduced 1991. (AVSA Reg. No. 7485) More information.
Halo-ing: Condition which describes a leaf which has chlorosis along the edge. Edges of the leaf appear yellow. The condition is most often associated with a nutrient imbalance, such as a deficiency of boron, molybdenum, nitrogen or phosphorus.
Hand-Pollination: Commonly-used method for producing African Violet hybrids. The method involves using a finger or some small instrument to simply move pollen from the anthers of one African Violet to the pistil of another. After four to six months, given that fertilization was successful, seeds will have developed. Upon germination, these seeds will grow into plants that will, hopefully, exhibit characteristics of both parent plants. Also see Cross-Pollination.
Hard Water: Water which has a higher concentration of minerals. Also see Soft Water.
Harlequin: Optimara variety. Large, standard African Violet (4-inch pot size) with single, bi-color flowers. Flowers are white with a wide red edge. Leaves are medium green. Introduced 1988. (AVSA Reg. No. 6947) More information.
Hawaii: Optimara variety. Medium, standard African Violet (4-inch pot size) with semi-double, bi-color flowers. Flowers are purple with a white edge. Leaves are medium green (red reverse). Introduced 1987. Improved 1995 and 1999. (AVSA Reg. No. 6558 and 8314) More information.
Heart-Shaped: Leaf type. Also called cordate. Describes a pointed African Violet leaf with a wide, rounded base, giving the leaf the appearance of a heart. This leaf type is often seen on miniatures and super miniatures.
Heating Box: See Rooting Box.
Heel: The stem of a leaf cutting. On African Violets, the heel should consist of about 1 to 2 inches of the stem. Also see Leaf Propagation.
Helsinki: Optimara variety belonging to the World Traveler series. Extra large, standard African Violet (6-inch pot size) with semi-double, two-tone pink flowers and dark green leaves. Introduced 1991. (AVSA Reg. No. 7913) More information.
Hiroshige: Optimara variety belonging to the Artist's Palette series. Named for the Japanese Ukiyo-e woodcut artist, Hiroshige. Medium, standard African Violet (4-inch pot size) with single, bi-color flowers. Flowers are light blue and white. Leaves are medium green. Introduced 1995. (AVSA Reg. No. 8315) More information.
Hisaku: Holtkamp variety (Europe). Medium, standard African Violet (4-inch pot size) with bi-color flowers. Flowers are blue stars with a white edge. Leaves are dark green. More information.
Hokey Pokey: Optimara variety belonging to the Little Dancer series. Compact African Violet (3-inch pot size) with frilled, blue flowers and dark green leaves. Introduced 1999. More information.
Holly (1): Leaf type. Also called holly-type. Describes an African Violet leaf which curls up around the edge. The curls are discontinuous, giving the leaf the appearance of a holly leaf.
Holly (2): Rhapsodie variety. Small, standard African Violet (4-inch pot size) with single, blue flowers and medium green leaves. Introduced 1995. (AVSA Reg. No. 8345) More information.
Holtkamp: See Holtkamp Greenhouses.
Holtkamp, Hermann Sr.: (1904-1988) Master Gardener and founder of Holtkamp Greenhouses. Responsible for developing many innovations, such as non-dropping flowers, which have contributed significantly to the worldwide popularity of African Violets. Hermann Holtkamp, Sr. is remembered as one of the most influential pioneers in the African Violet industry.
Holtkamp Greenhouses: The largest grower of African Violets in the world. Founded by Hermann Holtkamp. Holtkamp Greenhouses is the originator of Optimara and Rhapsodie varieties. Their research and development efforts are some of the most respected in the industry, creating many new varieties, each year, in both the U.S. and Germany. Holtkamp Greenhouses is credited with a number of notable innovations, including multiflorescence, semper florescence and non-dropping flowers. Many of Holtkamp's most recent innovations have evolved out of their Space Violet program.
Honeydew: A shiny, sticky substance left on African Violets and other plants by certain insects. Honeydew will often host a thin, black fungus called Sooty Mold. Insects which secrete honeydew include Aphids, Scale and Whiteflies.
Hopi: Optimara miniature variety. See Little Hopi Girl.
Hormone: See Growth Hormone or Rooting Hormone.
Houston: Optimara variety. Small, standard African Violet (4-inch pot size) with single, dark blue flowers and medium green, girl-type leaves. Introduced 1990. (AVSA Reg. No. 7348) More information.
Hula Hula: Optimara variety belonging to the Little Dancer series. Compact African Violet (3-inch pot size) with frilled, lilac flowers and medium green leaves. Introduced 1999. More information.
Humidity: Air moisture measured as relative humidity, the actual moisture content in the air divided by the moisture content in fully saturated air at a given temperature, i.e., the percent of moisture which the air is capable of holding at its current temperature. From this, relative humidity is stated as a percentage. Ideal humidity for African Violets is 70 to 80 percent. Given that this level of humidity would be difficult to maintain in most homes, it is generally recommended that African Violets receive at least 50 to 60 percent humidity. Humidity is measured with an instrument called a hygrometer. More information.
Hybrid: A variety which exhibits a combination of characteristics from two different parent plants. New hybrids are grown from seeds which have been produced by cross-pollination.
Hybridizer: Term referring, most often, to a commercial grower which is engaged in the development and cultivation of new hybrids (see Holtkamp Greenhouses). However, the term may apply to anyone who produces hybrids.
Hydroculture: A variation of hydroponics which requires the use of a specialized container consisting of an outer pot and an inner pot. The inner pot contains an inert potting medium which primarily serves to support the roots. The outer pot serves as a reservoir for water and nutrients. Because the inner pot is made of an open mesh material, water and nutrients are allowed to flow from the outer pot to the inner pot, where they are absorbed by the roots.
Hydrogen: (H) Major element essential to the growth and vitality of African Violets. Sometimes called a free element. Hydrogen is absorbed from water. Through the process of photosynthesis, hydrogen combines with carbon and oxygen to form plant carbohydrates.
Hydroponics: Any method of growing plants in which water is the primary growing medium. In hydroponics, no soil is used. Instead, the roots are placed in direct contact with a solution of water and nutrients. Also see Hydroculture.
Hygrometer: Instrument for measuring humidity.
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