Clematis paniculata [klem-AT-iss, pan-ick-yoo-LAH-tuh] is commonly known as Sweet Autumn Clematis.
It also has several different Latin names, such as:
- Clematis maximowicziana
- Clematis dioscoreifolia
- Clematis terniflora
This perennial vining plant hails from Japan, and with its rapid growth and abundant, fragrant flowers, it is a popular addition to the summer garden around the world.
Clematis Paniculata Care
Size & Growth
The fast-growing deciduous Sweet Autumn Clematis vine is winter hardy to USDA hardiness zone 4.
Early in the spring, White Clematis emerges from its slumber and produces tiny, pale green leaves.
As warmer weather comes, it begins to grow in a rampant fashion and soon can reach a height of 30′ feet if it has tall, sturdy structures upon which to climb.
The vines will quickly cover fences and sheds and are especially fond of twining through chain-link.
The serrated, semi-evergreen leaves transition from pale green to deep green as the season progresses.
The shiny, leathery, hairless, elliptical leaves grow in an alternating pattern along the vines.
Flowering & Fragrance
Sweet Autumn Clematis blooms in late summer and will persist through October.
Its flowers are unusual and differ from other species in the Clematis vine family by being smaller, more delicate, with amazingly fragrant flowers.
The creamy white flowers are about an inch across and have a scent reminiscent of vanilla.
They are extremely attractive to honeybees, hummingbirds, and other pollinators.
In the fall, the flowers transition into fluffy, silvery-white seed heads.
They produce seeds in a rambunctious fashion and are enthusiastically self-seeding in the southern United States.
Light & Temperature
These hardy plants can grow well in light settings ranging from partial shade to full sun.
In fact, they tend to thrive in shady or partially shaded settings.
Although the plants prefer a warmer, more tropical setting, they can do well in USDA hardiness zones ranging from 9B to 4A.
It’s important to keep the roots cool, so you should lay flat stones around the base of the plants or surround them with a shallow-rooted perennial groundcover.
Watering & Feeding
When watering do not wet just the soil surface. These deep-rooted plants require deep watering.
Water slowly and thoroughly about once a week – more often during hot, dry weather.
Fertilize generously with low nitrogen (e.g., 5 – 10 – 10) fertilizers in the springtime after the buds have emerged.
Wait until they are about 2″ inches long and then begin fertilizing.
Your next feeding should be about a month later.
This time use a balanced fertilizer, such as 10-10-10.
From then on, fertilize monthly, and alternate between low nitrogen and balanced fertilizers.
Continue through the end of the growing season.
Soil & Transplanting
Purchase young paniculata Clematis vines at most garden centers early in the springtime.
When you bring your small plant home, simply transplant it into any sort of average garden soil.
Rich soil with a neutral pH is preferred, but these plants are very tolerant of almost any pH level and almost any type of soil as long as it is well-drained.
It should neither be soggy nor extremely dry.
Position the plant’s crown about 3″ or 4″ inches below the surface of the soil to protect dormant buds, which will provide a backup of new growth in the event the existing stems don’t survive.
Mulch around the plants, place flat stones around them or plant a perennial groundcover to help keep the soil cool around the plants’ roots.
Be sure to provide some sort of support right away.
You’ll be surprised at how quickly your little plants begin growing and seeking to climb.
Grooming & Maintenance
You’ll begin to see new leaf buds during the months of February and March.
It’s a good idea to perform a light pruning at this time.
Look sweet autumn clematis over and remove any dead stems and leaves.
Remove old, mildewed foliage and vegetation, too.
Because this plant is such a vigorous grower, you’ll need to keep up with it throughout the growing season.
It may tend to take over and cover other plants or structures.
If it does this, simply wrap up handfuls of it and chop them off.
It will not negatively affect the plant and will soon be growing over objects and plants again.
In late summer and early in the autumn, you may get one last burst of fragrant blooms from your clematis this may persist until your first frost.
When these blossoms subside, give your vines a hard pruning.
Cut them back to about a foot above the ground.
How to Propagate Clematis Paniculata
In conducive climates, these plants are vigorously self-sowing, and you will have more of an effort to prevent propagating them than you will propagating them.
If you live in a cooler climate, you may need to grow them from seed indoors late in the wintertime.
Alternately, grow them from cuttings.
Here’s how:
- Put some sterile potting mix into a 2″ inch pot.
- Trim off a 3″ inch branch from the parent plant’s main stem.
- Trim off the bottom leaves of the cutting, leaving several leaves at the tip.
- Poke the snipped end of the cutting into the prepared potting mix.
- Water the potting soil thoroughly and keep it evenly moist throughout the rooting process.
- Within a month to six weeks, you should see new roots growing out through the drainage holes of the pot.
- Transfer the cutting to an 8″ inch pot filled with good potting soil, or transfer it to its permanent place outdoors.
- Water thoroughly and keep the soil evenly moist from here on out.
Related: How To Grow Clematis In Pots
Clematis Paniculata Pest or Diseases
Although Sweet Autumn Clematis is quite rugged, it is susceptible to a fungal infection, which may cause the vines to wilt suddenly and turn brown.
If this happens, you’ll need to prune the dead growth quickly.
Don’t compost the pruned vines.
Dispose of them in a sealed plastic bag.
Be sure to clean your pruning shears with bleach immediately after performing this pruning.
The crown of the plant should send up fresh, unaffected growth very soon.
Surprisingly, this otherwise hardy plant will wilt and die unless it is handled quite gently.
Whenever you are propagating or transplanting, be sure to handle with care.
Is The Clematis Terniflora Toxic or Poisonous?
All parts of this plant are poisonous and can cause contact dermatitis.
Be careful when handling Clematis, and be sure to wear gloves and wash thoroughly after pruning or transplanting.
If ingested, the toxin, Anemonin, can cause mouth ulcers and burning sensations in the mouth.
If burned, the resulting smoke is toxic.
Is Sweet Autumn Clematis Invasive?
As mentioned, Sweet Autumn Clematis is an enthusiastic self sower.
Its seed heads are designed to facilitate being blown around.
In the southern United States, it is very easy for this plant to escape cultivation and become quite invasive.
In the northern states, this is not much of a problem as the seed cannot survive cold, snowy winters.
Suggested Clematis Paniculata Uses
If you want a fast-growing vine that will cover up an unsightly shed or provide an excellent privacy screen or trellis plant while attracting hummingbirds, butterflies, honeybees, and a wide variety of other pollinators, Sweet Autumn Clematis is the vine for you!
It’s an excellent choice for a naturalized garden, wildlife gardens, or for trellises because, despite its being toxic to humans, it provides food for wildlife.
Even so, it is deer resistant.