Rivercities Garden Club

Meeting 2/3/02

 

Program - Club roundtable for gardening

GARDENING ROUNDTABLE

Jim Collins -HYDRANGEAS

Two excellent references: 1. Church, 0. 2002. Hydrangeas. Fire Fly Books, New York. ISBN

1-55208-521-5. $16.95 2. Lawson.HaIl, T. and Rothera, B. A Gardener s Guide. Timber

Press.

Most times when we think of hydrangeas, we think of the large-leafed, round flower heads (mopheads). However, there are many other types as presented below. Hydrangeas are some of the most resistant garden shrubs, tolerating coastal winds, some tolerate shade if not too dry or dense and most grow in acid or alkaline soils. Not possible for most all plants.

Hardiness: Hydrangea arborescens —zone 3-9, H aspera ---zone7-9, H macrophylla —-zone 6-9, H. paniculata ---zone 3-8, H quercjfolia ---zone 5-9 and H serrata --- zone 5-8.

The first hydrangea discovered and introduced to gardens was the North American Hydrangea arborescens, collected by John Bartram in the 1730 s. Later, he and his son discovered H querc~fol Ia, native to Georgia. A large number of hydrangeas has been discovered in Japan, China and North America. Family name is Hydrangeaceae.

Most hydrangeas are hybrids, bred by German, Swiss and French breeders.

Hydrangea flowers— most common is H. macrophylla. Flowers: mophead or lacecap. Mophead hydrangea flowers are made up of infertile flowers with a few fertile flowers.

The flowers with the big sepals (instead of petals) are sterile and cannot produce seed. The fertile flowers are very small, capable of producing seeds.

Lacecap flowers have a flat plate-like flower that has a row or 2 of big sepal flowers around a rim and mass of tiny true flowers in the middle of the plate. These flowers do not last as long as mophead flowers since they produce seeds. (the name "lacecap" originated from the lace caps once worn by servant girls in the stately homes of Europe.

True flowers, which are fertile and produce seeds, are shaped like a vessel and gives the name "hydrangea", as the seed capsule is shaped like a Greek water vessel. The 2 Greek words make up the word hydrangea: hydra water and angeion = a vessel.

Most wild species of hydrangeas have lacecap —type flowers, although a few have panicles of flowers. These are long, pointed flower heads where the flowers open in succession, with the oldest at the base. H. querc~floria and H. paniculata both have panicle flowers. "paniculata" comes from the Latin name for panicle.

Wild hydrangea species and cultivated form:

H arborescens (often called the North American hydrangea) is "tree-like." Found in Appalachian Mountains from New York to Florida. 2 well-known varieties: Grandiflora and Annabelle.

H aspera, a little known species from China, but has some interesting features.

H heteromalla, of Himalayan origin. Very large plants, up to 16 feet.

H macrophylla. Well known. "Macro = big and ‘phylla = leaf, thus macrophylla = big leaf. Bears flowers on year-old wood. Mophead or lacecap flowers. Origin Japan. Tolerates shade, sun, wet soil, frost.

H. paniculata. Panicle hydrangea or tree-form hydrangea. Panicles of white flowers. Hardy to zone 3. Height may reach 20 feet. Bears flowers on new wood, so can be pruned severely in late winter.

H quercjfolia. Oak-leaf, native to southern states of eastern USA. Grows to 5 feet tall and 7 feet wide. Grows best in sun, has large cones of creamy white flowers. Subject to root rot.

H. petiolaris. Climbing hydrangea. Attractive, exfoliating bark in dormant season. Vigorous grower after first year. If uninhibited, may grow to 70 feet in trees. Small, white panicle of flowers.

Pruning and propagation will be discussed.

Fertilization: apply 10-10-10 biannually. A gardener on HOly stated that one should add the fertilizer twice in spring and twice in the fall.

Soil acidity

1. For the color of changeable hydrangeas: in general, blue color shows when the soil pH is 6.5 or lower with the more intense blues being at the lower pH range. As pH climbs to 7 or above, these same plants will exhibit pink or reddish colors. In neutral or alkaline soils, the pink and red varieties stay true and not tend toward mauve or lilac as may occur at low pH.

The color difference has to do with ability of the plant to absorb aluminum. The most often mentioned bluing agent is aluminum sulfate. Treatment of plants: prepare a solution of ¼ oz aluminum sulfate and ~/4 oz sulfate of iron mixed in 1 gallon water. Apply up to 2 gallons, never more, in spring and fall. May add elemental sulfur to lower pH.

Blood meal encourages intense colors (due to the iron absorbed by the plant). Lime raises soil pH and encourages the pink and red colors.

2. The whites remain white at different soil acidities.

3. Some commercial hydrangea growers and gardeners advocate allowing the plant to flower in soil where pH is not altered since it is difficult to alter pH and keep it so.

Selected web sites: www.hvdrangea.com, www.heronswood.com and www.hvdrangeasplus.com.

Hydrangeas are available from many sources: the web sites above and others, local nurseries, Wayside Gardens and many others, Louisiana Nursery at Opelousas, La, various nurseries at Forest Hill, LA and from other gardeners.

Carie Her comments were about using plants for borders. Sunny border veronica has numerous small blue flowers that persist for the entire summer. The leaves become bright red in the fall and the plant is resistant to mildew and insect pets.

Ragin cajin has fuzzy leaves with fire red flowers. This plant survives the summer very well.

She contributed the interesting fact that poneers put rose cutting in a potato to keep them moist. The Greenwood Cemetary management wants the old roses to create the image of the way flowers were years ago. She is going to do project for Colonial Dames

Isen Gilespie mentioned that the Church garden of the Korean Prsypterian Church in Bossier City needs a lot of help. The church does not have much money as a lot of the older paritioners have died, and a number of the younger members have been pulled away as a result of the "War on Terrorism." Isen asked for donations of plants for the garden and perhaps for some help.

Kaye Reilly is a bulb grower. She purchases them from wholesalers and will make the catalogues available to the club.

Orental lillies will come back again if they are not disturbed especially if a clay pot. The lillies that she had planted in the garden are now gone. They need lots of drainage but also like shade and moisture. Consider planting with ferns. The result is really pritty and the ferns supports the lilly stems.

Asiatic lillies will come back for three years.

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