Climbing Hydrangeas and Their Look Alikes
When the garden is full, the only way to go is up.
You can take advantage of that vertical space
with carefree climbing vines that so beautifully fit the bill.
There is a group of these vines that are so
similar in appearance that it takes some examination to tell them apart.
If you look closely
in a not overly civilized part of your garden, you will probably find some
specimens of our native Decumaria barbara.
This semi-evergreen, woody-stemmed
climber is frequently called climbing hydrangea.
It is, in fact, in the family of Hydrangeaceae.
The shiny ovate (pointed oval) leaves are
two to four inches long. The vine climbs
along the ground until it finds a tree to hang onto.
It will grow happily as a groundcover, but
will not flower until it attains some height.
The aerial rootlets of Decumaria will help you
identify it. While it will climb on its own, it may need some encouragement to
climb the tree or structure that you choose. Once started, it climbs and begins to branch horizontally at regular
intervals, giving the plant a very architectural presence in the garden, with
or without leaves. The outstretched branches reach to two feet, with the main
vine hugged closely to the tree trunk by aerial roots. In May, a mature vine will be covered with
small, fragrant, flat-topped, white flower clusters at the ends of the extended
branches.
D. barbara prefers moist
situations and acid soil. It will grow
in the shade, but flowering improves in more light.
Stem cuttings, taken in late summer or early
fall, will take fairly easily, but once established it seeds itself in,
providing small plants to be moved elsewhere or shared.
A Chinese counterpart, D. sinensis,
is available.
A more elegant form of this native is the Hydrangea
anomala ssp. petiolaris, the climbing hydrangea, which is now widely
available at retail nurseries. It is
also a deciduous, woody-stemmed climber, but the vine has exfoliating red bark
as it ages, adding to the winter interest.
The five-inch flower clusters contain not only the small white flowers
of the native vine, but are surrounded by up to one and a half-inch sterile
flowers which dress it in lace. It
flowers best in bright light with adequate moisture, but will tolerate planting
against a north wall. In Georgia’s
climate, full sun is too strong for this vine.
The shiny, dark green leaves of
H. petiolaris are more
oval than it’s cousin, and are finely toothed along the edges.
The outstretched branches of H. petiolaris are
slightly longer than Decumaria’s, at almost three feet.
Both types have graceful downward curves in
their side branches. The vine has the
potential to grow to 50 feet in height, and to surround its base, like a skirt,
in ground covering vines. It prefers
well-drained, organically enriched soil and, once established, can tolerate
some dry conditions. The vine can be
allowed to climb a mature tree or a masonry wall, but should not be trained on
a wooden wall as the aerial roots would cause damage.
The seed heads dry well and contribute airy
filler to the base of dried arrangements.
Schizophragma
hydrangeoides,
Japanese hydrangea vine, is considered by some to be
even more elegant than H. petiolaris.
For many years, it was quite difficult to
find. All the conditions required by
the previous two vines mentioned apply to this vine as well, although it may
appreciate slightly more shade. The
broadly oval leaves are four to six inches and the flower heads are
larger. The cultivar ‘Moonlight’ has
silvery-green leaves that turn and shine in a breeze. You may propagate it by
seed in spring and by greenwood or semi-ripe cuttings in summer.
It can be expected to reach a height of 30 to
40 feet. A variety that offers larger,
pink flowers, ‘Roseum’, has recently become available.
According to Gene Griffith, of Wilkerson
Mill Gardens
in Palmetto,GA, S.hydrangeoides is “coarsely dentate and nearly glabrous”, or
smooth leaved, with coarsely toothed leaf
edges. Its cousin, Schizophragma
integrifolium, has larger leaves, with hairy or pubescent reverse and
less, to barely any, indentation in the margins.
Schizophragma integrifolium
the Chinese climbing hydrangea,
has lacecap type flower heads surrounded by
an outer whorl of distinctive white sepals, and is worth seeking out.
The leaves reach 6 inches in length and the
flower clusters can be as much as ten inches across.
It is the shortest of the group, expected to
reach a conservative 12 feet, which brings these beautiful blooms within
sight. It is not as hardy as S.
hydrangeoides, but should succeed as far north as Zone 7.
The only true evergreen in this group is Pileostegia
viburnoides (Syn. Schizophragma viburnoides).
It grows in sun or shade, in well drained
soil, but attains a height half that of most of it’s
relatives, topping out at 20 feet. The
tiny, creamy white flowers have many prominent stamens. The difficulty would be
in finding a source of this vine. An
internet search turns up sources in England,
Italy and The
Netherlands.
A beautiful picture of the plant is available at www.esveld.nl/htmldia/p/pivibu.htm.
An archival newsletter from the J.C. Raulston Arboretum at North
Carolina State
University,
indicates that in 1992 there was a Pileostegia planted near the white
garden. The vine had grown to 18 inches
in eight years. Arboretum staff
conjectured that the slow growth of the young plants made them uneconomical for
trade.
None of these vines requires pruning or has any pests or
diseases of note. Moisture is their only
requirement and you may get leaf drop from some with drought.
So plant them where they can climb, water
when necessary, and let them go. No
matter which of these vines you choose and grow, they will raise your eyes from
the garden floor and put on a show that can be appreciated from across the
garden.