Shrub · Ranunculaceae
Clematis
Clematis
Give it sun on its head and shade on its feet, and clematis climbs into a wall of bloom.
Full sun
Every 5–7 days
USDA 4–9
8–12 ft · 2.4–3.7 m
Overview
There's a reason clematis goes by the queen of the climbers. A member of the buttercup family, Ranunculaceae, it spans everything from tough wild species to the large-flowered hybrids that drape an arbor or trellis in saucer-sized blooms. Plant it anywhere across USDA zones 4 to 9 and it'll come back as a hardy perennial vine, year after year.
When the flowers show up depends on the type. Plenty open in late spring to early summer, then loop back for an encore in late summer to early fall. The way clematis climbs is worth knowing too: it twists its leaf stalks around slim supports, so it needs wires, netting, or a thin frame to grab onto instead of a solid post.
Clematis pays you back for patience more than fussing. Set it deep, keep the roots cool and damp while the top soaks up sun, and prune to suit its bloom group. Nail those few things and a young vine digs in for decades of bloom.
Care
The short version: full sun on the top with cool, shaded, evenly moist roots below, rich well-drained soil, and pruning matched to the plant's bloom group.
Light
Clematis blooms best in full sun, ideally 6 or more hours a day, though it'll get by with partial sun or light shade. That old saying really does hold up: head in the sun, feet in the shade, since hot, exposed roots will cut into the flowering.
Water
Aim to give clematis at least 1 inch (2.5 cm) of water a week, and more when it's dry, and don't ever let the root zone cook. Pile on the mulch to lock in moisture and keep those roots cool while the top sits in sun. A steady drink every 5 to 7 days keeps it growing strong.
Soil
Go for rich, fertile, well-drained loam, but clematis will put up with clay or sandy ground once you've amended it. It's easy about pH, happy anywhere from 6.0 to 8.0, so most garden soils work fine once you've dug in some compost.
Temperature
This is a tough plant, shrugging off winters down to -29°F (-34°C) and summers up to 95°F (35°C). That cold hardiness is exactly why it does so well as a perennial across zones 4 to 9.
Humidity
Regular outdoor humidity suits it just fine, so there's no target number to fret over. What counts a whole lot more is good air movement, because still, crowded growth is an open door for powdery mildew and stem rot.
Feeding
Give it a balanced fertilizer in spring as growth kicks off, then on through the season. Skip feeding while it's in flower, and keep the nitrogen light, since too much pushes soft growth that wilt loves to go after.
Pruning
Prune by bloom group, because cut the wrong type at the wrong moment and you've traded away flowers. Group 1 old-wood bloomers want just a light trim straight after flowering, Group 2 large-flowered hybrids get a light prune down to the topmost plump buds in late winter, and Group 3 new-wood types are cut hard to 2 to 3 feet in late winter.
Repotting
Clematis hardly ever needs repotting, and it doesn't appreciate having its roots disturbed. Only move it when roots start circling or pushing out of the pot, growth stalls, or the soil empties out far too fast.
Size & spacing
A grown vine reaches 8 to 12 feet (2.4 to 3.7 m) tall and fills out 2 to 6 feet (61 to 183 cm) wide. Hand it that space along with a support to twine through, so air keeps moving around the leaves.
When to plant
Get clematis into the ground in spring or early fall, when the soil's easy to work and the weather's mild. Set it deep, with the crown an inch or two under the surface, and it'll root in before the heat or cold arrives. The first flowers should turn up in late spring to early summer, with a second flush often following later in the season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: spring or early fall
- Harvest: late spring to early summer, often reblooming in late summer to early fall
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Most of what goes wrong with clematis turns up on the stems and leaves, whether it's a shoot that drops overnight or a dusty film spreading across the foliage. Spot it early and you can clip the trouble out before it gets going. Find what matches what you're seeing below, then act while it still does some good.
Why did a whole shoot keel over the moment buds opened?
When a single shoot suddenly flops and goes black right as buds or flowers show up, while everything else stays green, you're looking at clematis wilt, a fungal stem rot. Check down low near the soil line for dark lesions on the stem. Snip every affected stem back to clean tissue or below ground, wipe down your pruners between cuts, and keep the water coming. If the crown went in a couple inches deep, the plant usually pushes up fresh shoots from below the next season.
Fix:
- Cut out and destroy all affected stems back to healthy tissue or below soil level
- Disinfect pruners between cuts
- Keep the plant watered; plants set with the crown a couple inches deep usually resprout from below ground the following season
What's chewing ragged holes in the new shoots and leaving slime?
Torn-up young shoots and ragged holes on a freshly planted vine usually point to slugs and snails, and the silvery slime trails give them away. No trails to be found? Head out after dark and look for earwigs tucked into the flowers and crevices. Sprinkle iron phosphate bait around the young plants, clear out debris and hiding spots, and set rolled cardboard to trap the earwigs until the shoots toughen up.
Fix:
- Apply iron phosphate slug bait around young plants
- Remove hiding places and garden debris
- Trap earwigs with rolled cardboard or shallow traps
What's the chalky white stuff on these curled, stunted leaves?
A dusty white film across the tops of the leaves, plus foliage that's small, curled, and misshapen, usually means powdery mildew has settled into still, crowded air. Give a leaf a quick wipe to tell it apart from plain dust, because this coating sticks and the leaf itself looks warped. Pull off the bad leaves, thin the vine so air can move, and keep water off the foliage. If it keeps creeping along, a labeled fungicide early on will help.
Fix:
- Remove affected leaves
- Improve airflow by thinning and proper spacing
- Avoid overhead watering
- Apply a labeled fungicide early in infection if needed
Why are the new shoots sticky and crawling with tiny bugs?
Little soft-bodied bugs, green or dark, clumped on the shoot tips, plus sticky honeydew and maybe some sooty mold or ants, add up to aphids working over the tender new growth. Flip a few young leaves to check the undersides and you'll spot them. For a light run, a blast of plain water knocks them off; otherwise reach for insecticidal soap every 5 to 7 days for around 3 rounds. Hold a systemic insecticide in reserve for the heavy, stubborn outbreaks.
Fix:
- Spray with insecticidal soap, repeating every 5 to 7 days for about 3 applications
- Hose off light infestations with water
- Use a systemic insecticide only for heavy, persistent infestations
Toxicity
Clematis isn't something to eat, and it isn't something to leave where pets can get at it easily. Every part holds protoanemonin, an irritant that forms once the leaves or stems get chewed or crushed, and the ASPCA lists the vine as toxic to cats, dogs, and horses. That bitter taste stops most animals before they eat much, but the sap can still sting skin and mouths, so give it a careful hand.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
A cat that nibbles the leaves or stems can start drooling, throwing up, and running loose stools, with a sore, irritated mouth to go with it. Lucky for them, that bitter, acrid taste usually calls it quits before they swallow enough to cause real trouble.
Dogs Mild
Gnaw on the foliage and a dog will likely drool, gag, and wind up with an upset stomach and a tender mouth. Most won't get far because the sharp taste puts them off fast, so a serious poisoning is rare.
Horses Mild
A horse that grazes the plant may end up drooling hard, turning away from feed, and dealing with mouth blisters and colicky discomfort. Given anything better to eat, though, horses tend to leave the bitter foliage alone.
Rabbits Caution
That same protoanemonin that bothers cats and dogs will sting a rabbit's mouth and gut too, so think of the vine as off-limits and keep it fenced away from runs and hutches.
Livestock Caution
Cattle, goats, and sheep can come down with mouth and gut irritation if they browse clematis, but that acrid taste keeps most of them clear unless the pasture's running thin. Best to keep the vine well out of reach of grazing stock.
Birds Caution
Thanks to that irritant sap, clematis is a poor pick around pet birds and poultry, so keep inquisitive beaks from pecking at the foliage and stems.
People Caution
None of this plant is food, and the sap can leave skin red and blistered or sting your mouth on contact. Slip on gloves before you prune and wash up after, and don't let little ones chew the leaves.
Sap can irritate skin; wear gloves when pruning and wash hands afterward.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Clematis comes in hundreds of species and cultivars, but a handful keep showing up in gardens. These are the ones worth knowing by name, along with the bloom group each one lands in.
Jackmanii
Here's a longtime favorite hybrid with big, velvety, deep-purple flowers. It's a Group 3 plant, flowering on new wood, so it gets a hard cutback every late winter.
Nelly Moser
This Group 2 large-flowered hybrid wears pale pink petals, each one striped with a deeper carmine bar. Strong sun washes out those colors, so a little shade keeps it looking its best.
Henryi
A strong-growing Group 2 large-flowered hybrid, it puts out big creamy-white flowers that pop against their dark anthers.
Sweet autumn clematis (Clematis terniflora)
Late in the season it covers itself in small, fragrant white flowers, but here's the catch: it self-seeds with such gusto and has gone so invasive across parts of the eastern US that gardens are better off skipping it.
Clematis montana
An energetic early species, this Group 1 type blankets itself in masses of small spring flowers. Prune it only lightly, and only once it's done blooming.
How to propagate
Multiplying clematis is slow going, but it's not difficult, and the easiest paths copy a plant you already have rather than fussing with seed.
LayeringEasy
Spring to summer · A few months to a year
Want the surest way to get more clematis? Layering. Anytime from spring through summer, pin a low, bendy stem down against the soil and let it root where it makes contact, then cut the new plant free once it's settled, which takes a few months to a year.
Stem cuttingsModerate
Late spring to early summer · Several weeks to months
Anywhere from late spring into early summer, take semi-ripe internodal cuttings off the current season's growth. Give them several weeks to a few months to root, and know that this one asks for a steadier hand than layering does.
DivisionModerate
Early spring · A season
In early spring, lift and split well-established crowns, taking it slow since clematis doesn't like having its roots messed with. Let the divisions have a full season to find their footing before they really take off.
Myths
Clematis is harmless to pets because it is just a flowering garden vine.
It belongs to the buttercup family and carries protoanemonin, an irritant the ASPCA flags as toxic to cats, dogs, and horses. A pet that chews it may start drooling, vomiting, running loose stools, and nursing a sore mouth. The bitter taste usually limits how much an animal eats, but that's a long way from harmless.
All clematis should be pruned hard every late winter.
What you do with the pruners hangs entirely on the bloom group. Group 1 flowers on old wood and just wants a light trim after blooming, the Group 2 large-flowered hybrids get a gentle prune, and only the new-wood Group 3 takes a hard cutback. Cut an old-wood type to the ground and you remove that year's flowers.