Panicle Hydrangeas are generally considered vigorous shrubs, but they actually become small trees under favorable conditions.
Plants 8’ to 12’ feet high are the rule in gardens, but there are records of specimens well over 20’ feet.
Panicle Hydrangeas’ Characteristics
Flaking gray bark characterizes the trunk and larger branches, and the natural outline of a bush is nearly globose.
The leaves vary in length from 2” to 6” inches and are frequently in whorls of three at the nodes.
In the typical form of this shrub, the large panicles are showy from August to October or even later in their pinkish or bronze stages.
The fertile or perfect flowers are small and relatively inconspicuous, but they are produced so abundant that the general effect is of great showiness.
The crowning touch, to be sure, in the display of the typical or wild form is due to the sterile flowers.
These average an inch across and are composed of four rounded sepals.
They also have longer stalks than fertile flowers. Consequently, they have held out a distance from the smaller blooms.
The combination of showy sterile flowers and the inner mass of perfect ones makes a particularly distinctive and lively effect.
Much of the same combination occurs in many viburnums, notably the cranberry bush types.
Hydrangea Paniculata
Hydrangea paniculata is known as Nori-utsugi (paste hydrangea) in its native Japan, about the traditional use of the bark in a paste made to manufacture paper.
The species grows wild as a woodland shrub throughout Japan and central China.
Much variation is shown in wild plants; specimens outstanding in one way or another were selected by Japanese connoisseurs over many years, frequently on pilgrimages to famous shrines or historic spots in the mountains.
These selections were grown in Japanese and Chinese gardens for a long time before their “discovery” by Siebold and later travel in the middle 1800s.
It is such selected garden forms as these that we know and not the wild Nori-utsugi at all!
Once introduced to America and Europe, the Japanese selections of this species have always been propagated by cuttings.
Voluntary Seedlings
Volunteer seedlings sometimes reach maturity often in moist situations (as noted in the new Gray’s Manual), but little notice is given to them.
These are usually much less showy than the garden forms, but if a large number were raised from seeds, it is almost certain that some very attractive new selections could be made.
Interestingly, in his Japanese travels in 1892, Professor Sargent of the Arnold Arboretum collected seeds of panicle hydrangeas in the forests of central Honshu.
Characteristics Of The Wild Type
Plants grown from these at Boston showed the characteristics of the wild type, but one specimen was outstanding for its unusually early flowers.
These opened in June, a good 6 weeks earlier than the rest. This trait proved consistent, and the plant was described as a variation. It is now called forma praecox, or early panicle hydrangea.
Late panicle hydrangea, forma tar-diva, differs in its nearly round sepals, often indented at the apex, and in the remarkable duration of its blooms.
Hydrangea Paniculata ‘Forma Floribunda’
Hydrangea paniculata forma floribunda is the most handsome of all. In fact, this is one of the most commanding hardy shrubs.
It has unusually long panicles of the same mixed flowers as the preceding, but the showy sterile flowers are formed with creamy white sepals so large that they overlap at the base.
Usually, they have a small red budlet at the center.
Rehder reduced these two variations to the rank of synonyms of typical Hydrangea paniculata, but this does not seem to be equitable treatment.
Numerous Sterile Flowers
Actually, they should have the same status as forma praecox. All three are clones.
While forma floribunda has more numerous sterile flowers than the others noted above, the prize in this respect at least must be given to forma grandiflora.
Peegee hydrangea, as it is called, has practically all sterile flowers, and the trim conic panicles of the wild type are bulged out into roundish masses singularly lacking in grace and distinction.
Most Inartistic Hydrangea
It is a great pity that this most inartistic hydrangea of the lot has been used to exclude the others in many plantings.
Panicle hydrangeas are the hardiest of the genus and stand at temperatures as low as 25° degrees Fahrenheit below zero. As a result, insect and disease troubles rarely affect them.
They are of special value in borders, backgrounds, and how to best take advantage of park and roadside plantings.
Effect of Boldness and Size
Both size and boldness of effect make them unsuited to foundation plantings except around very large buildings.
They are widely available from nurseries at moderate prices. In fact, these are consistently among the cheapest hardy shrubs.
All do best in a fertile loam with a generous supply of moisture. The light shade suits hydrangeas admirably but for these full exposure is also satisfactory.
44659 by Ben Blackburn