is a member of the Ranunculaceae (buttercup) family. The word
is from the Greek and means "vine." This genus includes approximately
250 species and numerous garden hybrids. It is a varied genus, made
up of mostly woody, deciduous climbing plants, though a few are
evergreen and a few herbaceous. There is great variety in flower
form, color, bloom season, foliage effect and plant height. Leaves
are opposite on the stem and mostly compound with three to five
leaflets. The leaf stalk twines like a tendril and is responsible
for giving the plant support. The flowers are showy, with four (sometimes
five to eight) petal-like sepals (no true petals) in numerous colors
and shades. There are three general flower forms: small white flowers
in panicles or loose and irregular spreading clusters, bell or urn-shaped
flowers, and flat or open flowers. The fruit is a ball shaped, "feathered" structure.
Clematis are hardy plants (many are hardy to USDA zone 3) and
can survive for 25 years or more. The large-flowered hybrids
may have blooms ranging from four to ten inches in diameter and
as many as 100 blooms per plant in a season. The species types
blooms ranging from one-half to three inches in diameter with
diverse shapes and habit; many of the species have fragrant blooms,
is not true of most hybrids. The one fault of clematis is that
they are not attractive during winter, when they are a tangle
There was little interest in clematis until the 1850s when many
were crossed and improved. Plants from Japan and China became the
parents of many hybrids. Much breeding occurred in Britain, France,
Belgium and Germany until about the 1890s; in fact, more new varieties
were introduced during this period than any other in history and
many clematis grown today originated then. The leading hybridizer
in Britain in the 1860s was the Jackman Nursery, which produced
C. x jackmanii (introduced in 1862), still the most popular clematis
grown today. In the 1880s, interest in clematis died down. Hybridizers
were running out of ideas and the wilt "epidemic" put a damper on
cultivation. Today, there is renewed interest in clematis, particularly
in very hardy and disease-resistant small-flowered types.
Clematis have a reputation for being difficult to grow--however,
like any other plant, if their needs can be met by the site and
proper care, they will thrive. Clematis require full sun to grow
best (6+ hours direct sun per day) though some dappled shade during
the heat of the day is beneficial. Flowers of some red and blue
large-flowered hybrids and the bicolors fade badly if they get too
much sun (such as 'Nelly Moser,' 'Hagley Hybrid' and 'Hybrida Sieboldiana')
and these should be planted in eastern exposures or partial shade.
The site should be open enough to allow for air movement around
the plants. Soil should be rich and well-draining with a pH close
to neutral (7.0). Though the plant's stems and foliage should be
in sun, the roots like a cool, moist environment. With the exception
of C. montana, clematis do not compete well with large tree
roots. Most clematis will require staking so the twining leaf petioles
can cling and climb upward, though some gardeners choose to let
the plants sprawl over the ground, over woodpiles, other plants,
Begin with a soil test to determine if the soil pH or the phosphorus
level needs correction. If so, make corrections before planting.
Soil in the planting area should be prepared to a depth of 24 inches
in an area approximately three feet wide. It is best to incorporate
one-third by volume some compost or rotted manure to help improve
aeration and drainage. See our GreenShare Factsheet on soil testing
for more information.
Consider the ultimate size and vigor of the clematis being grown
and match this to the support needed. Some support should be provided
for vines unless they are left to scramble over walls, small trees
or shrubs, or to sprawl over groundcover beds or grass. Supports
must be thin and wire-like since this plant climbs by twining petioles
that cannot grasp thick branches or heavy trellising. If growing
clematis on a wall or fence, string galvanized or plastic coated
wire to form six- to twelve-inch squares. Fasten this to the wall
with eye bolts three to four inches from the wall to allow for ventilation
and space for the vine to twine. Latticework or trellises can also
be used if placed a few inches from the wall for ventilation and
if large enough to support the vine. Poles can also be used for
supporting smaller, less vigorous vines; these are isolated vertical
features often surrounded by lower growing herbaceous plants. Arbors
and pergolas are suitable for the larger, more vigorous types of
Plants are readily available in garden centers and through catalogs
for spring planting, though they may also be available for fall
planting. Catalogs may offer a greater selection of species and
cultivars than are available locally. Clematis are most often container-grown
as they do not withstand much root disturbance. The species and
small-flowered hybrids have fibrous roots that are susceptible to
root damage; disturb roots as little as possible. Plants may also
be available bare root. These should be obtained in early spring
and planted while still dormant. Select plants that have multiple
stems, healthy, dark green growth and a root system that fills the
container. If beginning with small plants, consider growing them
in gallon pots during the summer in order for them to gain some
size. Fertilize these plants through the season and plant them in
the ground in the fall. Early September is a good time to plant
to allow for good root establishment before freezing weather.
amending the native soil for planting, dig a hole to accomodate
the root system. Cut stems back to 12 inches in height. This will
help the plant branch as it begins to grow and will reduce the chance
of stem breakage during the planting process. Clematis are planted
with the crown one to two inches below the soil surface (this enables
the plant to recover should it be mowed off, damaged by animals
or infected with clematis wilt). Once the plant is in the hole at
the proper depth, fill in with the backfill soil, firm and water
well to settle soil around the root system. If planting bare root
plants, soak the roots in a bucket of water for an hour before planting
to fully hydrate them. After planting, place a protective collar
of hardware cloth or chicken wire around the base of the plant to
protect against damage from mowers, string trimmers and animals.
Because clematis prefer a cool root environment, plan to underplant
with a groundcover or perennials that have shallow, non-invasive
roots. Artemisia 'Silver Mound,' hardy geraniums, creeping phlox,
coralbells, candytuft and most veronicas work well. A two-inch layer
of mulch, low shrubs, or paving also provides a cooler root environment.
Clematis may seem a bit slow to establish. In the first season,
there may be little growth and few or no blooms. However, it is
important to get the roots well established. Fertilize annually
for rapid growth during establishment with a 3:1:2 or 4:1:2 ratio
fertilizer. Apply one-half pound of a 15-5-5 fertilizer to the soil
in the 50 square feet surrounding each plant. Fertilization may
not be needed or desired once the plant is established and growing
well. Plants will need about one inch of water per week during the
growing season applied through irrigation or rainfall for good establishment.
Once the plant is well established, some basic care is needed on
an annual basis. In dry seasons, watering deeply once a week is
recommended. Renew mulch to a two-inch depth in late spring after
the soil has warmed unless a groundcover or other method is used
to cool the root environment.
Clematis can be transplanted in the fall, late winter or very early
spring before growth begins. Dig as large a root ball as is possible
(make sure soil is moist); the more roots preserved, the less the
transplanting process will hinder the plant's growth. Make sure
all the site requirements are met in the new location before moving
main purpose in pruning is to help plants produce the maximum number
of flowers. Annual pruning is recommended. Sometimes older, neglected
plants can be cut back into older wood and new buds may break. Growth
from old wood will likely be weak and slow, however. If no pruning
were done at all, plants would still grow and flower profusely,
though not where you may want them to. Some flowering would occur
high in the plant and out of sight. Not all clematis can be pruned
in the same way. There are three methods that can be applied to
major groups depending on the time of year the plant flowers. No
new growth must occur to enable the earliest flowering clematis
to bloom, but the later flowering types must make new growth in
order for flower buds to form. A few plants are not strictly bound
to the following groups but may cross lines. Because vines will
likely be entangled, make cuts carefully among the intertwining
vines and spread and train them in various directions in order to
cover the maximum possible area. This enables the plant to display
its blooms rather than be bunched up.
A: Early-flowering Clematis
Plants in this group bloom in early spring, generally in April and
May, from buds produced the previous season. Prune these back as
soon as possible after bloom but no later than the end of July.
This allows time for new growth to produce flower buds for the next
season. Remove shoots that have bloomed. You can prune out more
vines to reduce the size or to form a good framework of branches.
Do not cut into woody trunks. Plants in this group include: C.
alpina, C. macropetala, C. armandii, C. montana and C. chrysocoma.
B: Large-flowered Hybrids
Large-flowered hybrids bloom in mid-June on short stems from the
previous season's growth and often again in late summer on new growth
(these blooms are smaller). Prune in February or March by removing
dead and weak stems, then cut back remaining stems to the topmost
pair of large, plump green buds. This cut could be a few inches
to a foot or two from the stem tips. Plants in this group have the
tendency to become bare at the base as they mature. Underplant to
help conceal the stems. You may be able to force a flush of new
growth from the base by cutting the vine back to 18 inches immediately
after the flush of bloom in June. Plants in this group include:
'Nelly Moser,' 'Miss Bateman,' 'Lasurstern,' 'Duchess of Edinburgh,'
'Mrs. Cholmondeley' and others.
C: Late-flowering Clematis
Plants in this group flower on the last two to three feet of the
current season's growth. Some types begin blooming in mid-June and
continue into the fall. This is the easiest group to prune since
no old wood needs to be maintained. In February or March cut each
stem to a height of about two to three feet. This will include removal
of some good stems and buds. Eventually the length of the bare stem
at the base will increase as the vine matures. Plants in this group
include: C. viticella, C. flammula, C. tangutica, C. x jackmanii,
C. maximowicziana, 'Perle d'Azur,' 'Royal Velours,' 'Duchess
of Albany' and others.
Homeowners may have success propagating clematis by cuttings or
layering. All types can be increased by cuttings taken in May or
June from half-hardened shoots of the current season's growth. Use
a rooting mix of two parts sand and one part peat and a rooting
hormone (available at garden centers). Supply high humidity, warmth
and light in order for the cuttings to root within four to five
weeks. The large-flowered hybrids will take more time to root; if
cuttings are taken in May, they may not root until late August.
If rooted by early August, plant them out. If no rooting occurs
until late August, hold plants over winter in pots and plant in
early spring. Layering is the easier method and can be done in the
fall. Choose a mature stem produced earlier in the season, or from
the previous season's growth. Secure it into the soil at the nodes
or bury a pot containing a mixture of equal parts sand and peat
and secure the stem into this. Rooting occurs within about 12 months
at which point the rooted sections can be detached and planted.
The most devastating problem of clematis is a fungal stem rot and
leaf spot caused by the fungus Ascochyta clematidina and commonly
called "wilt." This is a disease on large-flowered hybrids. Small-flowered
hybrids and the species and their cultivars are less susceptible
to wilt. Symptoms include a sudden stem collapse typically as the
flower buds are about to open, and within a few days, the stem and
leaves turn black. Only one or perhaps several stems in a plant
may wilt. The stem discolors and may exhibit lesions below the first
pair of wilted leaves. Any part of the plant can be attacked down
to and just below the soil level. The usual treatment is to remove
the diseased stem below the wilted section, even below soil line.
Plants usually recover from buds lower on the stem. Powdery mildew
is another fungal disease that can occur on flowers and young stems,
usually in July and August. It should be treated with a fungicide
when first noticed as the fungus can disfigure leaves and flower
buds, causing them not to open. Mildew often occurs on plants in
poorly ventilated locations. If this is the case, consider moving
the plant. Aphids may feed early in the season on new growth. Slugs
may attack newly planted plants or even feed on bark of young stems.
Earwigs may feed on blooms and foliage or bore into unopened flower
buds. Rabbits and mice may feed on or girdle stems. Birds may feed
on overwintering buds.
Species and Small-flowered
C. alpina - 6 to 8 feet in height,
blooms April-May. Flowers on long stalks, 1.5 inches nodding, bell-shaped
or purple-blue in color. Seed heads are grey fluffy balls holding
until winter. Hardy, fool-proof plant. Group A pruning.
C. alpina 'Candy '- 6 to 8 feet in height, blooms April-May.
Blooms have light pink outer sepals, pastel pink inner; stamens
are green. Group A pruning.
C. armandii - 15 to 30 feet in height, blooms April-May.
Two-inch diameter blooms, creamy white in large axillary clusters;
has a strong vanilla scent in warm weather. Strong, vigorous grower.
Group A pruning; can cut to base to rejuvenate vine.
chrysocoma - 20 feet in height, blooms May-June. Long stalked
flowers 1.5 to 2 inches in diameter occur in axillary clusters;
pale mauve-pink with creamy stamens. Some bloom occurs in late summer.
New foliage is bronze-red. Group A pruning.
C. flammula - 15 to 20 feet in height, blooms August-September.
Flowers occur in terminal clusters in great masses; are 1 to 1.5
inches in diameter, white. Grown from seed so growth can be variable.
Group C pruning.
macropetala - To 15 feet in height, blooms April-May. Flowers
are double, nodding bells, 2.5 to 3 inches in diameter, pale blue
with purple shading. Seed heads last into winter. Foliage is neat
and attractive; plants prefer cooler, shady location. 'Snowbird'
is pure white with a hint of green on inside of bloom. Group A pruning.
maximowicziana - To 30 feet in height, blooms in September.
Flowers are 1.5 inches in diameter, cruciform, white. Very vigorous
grower. Group C pruning.
montana - 20 to 30 feet in height, blooms May-June. Flowers
are white, 2 to 2.5 inches in diameter and some cultivars have a
vanilla scent. One of the easiest to grow and propagate; very vigorous.
Group A pruning.
tangutica - 10 to 15 feet in height, blooms July-October. Most
common yellow flowered form. Flowers are 1 to 1.5 inches in length
and nod on a long stalk, singly or three to a stem. Seed heads are
spectacular, lasting into winter. Group C pruning.
viticella - 10 to 12 feet in height, blooms July-September.
Flowers slightly nod, are 1.5 to 2.5 inches borne singly or in
on a slender stalk; rich deep purple with small green stamens.
Vigorous and easy to grow. Group C pruning. 'Abundance' is bright
red with deeper red veins and creamy green
stamens. 'Etoile Violette' has slightly larger blooms that are
deep purple with creamy-yellow
'Barbara Jackman' - 8 feet in height, flowers May-June. Vigorous,
bushy plant. Flowers are 4 inches in diameter, deep purplish-blue
with bright magenta bar and large, creamy-yellow stamens. Fades
to mauve-blue. Group B pruning.
de Bouchard' - 6 to 8 feet in height, flowers July-August. Easy
to grow, prolific bloomer; a good plant for smaller spaces. Flowers
are 4 to 6 inches in diameter, pink with creamy stamens. Group C
'Hagley Hybrid' - 8 feet in height, flowers June-September. Flowers
are 4 inches in diameter, pale mauve pink, fading to a washed out
pink. Stamen filaments are white and anthers purple-red. Vigorous
grower. Group B/C pruning.
x jackmanii - 8 to 10 feet in height, blooms July-August. Flowers
are 4 to 5 inches in diameter and deep bluish-purple. Free flowering.
Group B pruning. 'Marie Boisselot'-8 to 12 feet in height, flowers
June-September. Opening flower buds are flushed with lilac-pink,
flowers are 8 inches in diameter, white with creamy stamens. Strong
grower. Group B pruning.
'Mrs. Cholmondeley' - 20 feet in
height, flowers May-October. A "foolproof" plant. Blooms are
light lavender blue, paler along the midrib, filaments white
and anthers brown. Group B/C pruning.
Moser' - 8 to 10 feet in height, flowers May-June and September.
Flowers are 8 inches in diameter, pale rosy mauve with a central
carmine colored midrib; dark maroon anthers. Flowers will fade badly
in full sun; provide some shade for this plant. Group B pruning.
'Niobe' - 8 feet in height, flowers June-September. Cup shaped bloom
opens dark ruby-red then turns to bright ruby red with cream stamen.
First flowers are 6 inches in diameter, later ones 4 inches in diameter.
Moderate grower with some bloom throughout the season. Group B/C
'Perle d'Azur' - 16 feet in height. Flowers continuously early summer
to mid-autumn. Blooms are 4 to 6 inches in diameter, sky blue with
green stamens. Group B pruning.
'Vyvyan Pennell' - 8 feet in height. Flowers June and September.
Flowers are 6 to 8 inches in diameter, double at first, single later.
Deep violet-blue blooms suffused with purple-red; golden stamens.
Group B pruning.
from Jane C. Martin, Ohio State University Extension, 2001
Photo Scott Bauer, ARS Image Gallery