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
Clematis has rightly earned the affectionate nickname queen of the climbers. A member of the buttercup family, Ranunculaceae, it spans everything from tough wild species to the large-flowered hybrids whose saucer-sized blooms drape a trellis or arbor. Right across USDA zones 4 to 9 it comes back faithfully each year as a hardy perennial vine, which makes it a wonderfully forgiving choice to start with.
Bloom time stretches out depending on which type you grow, so there is plenty to look forward to. Many open in late spring to early summer, then loop back around for an encore in late summer to early fall. The vine climbs by curling its leaf stalks around slim supports, so offer it wires, netting, or a narrow frame to catch hold of rather than a chunky post.
More than anything, clematis pays back a little patience. Set it deep, keep its roots cool and moist while the top soaks up sun, and prune it to suit its bloom group. Manage those few simple things and even a young vine will settle in and reward you with decades of bloom, so you can relax and enjoy watching it grow.
Care
The short version: sun on the top with cool, shaded, evenly moist roots underneath, rich well-drained soil, and pruning that matches the plant's bloom group. Get those right and the rest tends to take care of itself.
Light
Clematis blooms its best in full sun, ideally 6 or more hours each day, though it happily accepts partial sun or light shade too. That old gardener's saying really does hold up: keep its head in the sun and its feet in the shade, since hot, bare roots will dial back the flowers.
Water
Offer clematis at least 1 inch (2.5 cm) of water a week, a little more when things turn dry, and never let the root zone bake. A generous layer of mulch locks that moisture in and keeps the roots cool while the top enjoys the sun. Steady, even watering every 5 to 7 days keeps it cruising along.
Soil
Set it in rich, fertile, well-drained loam, though clematis copes happily with clay or sandy ground once you have amended it. It is easygoing about pH across a wide stretch from 6.0 to 8.0, so most garden soils will please it after you work in some compost.
Temperature
Clematis is a hardy soul, shrugging off winters as cold as -29°F (-34°C) and summers as warm as 95°F (35°C). That sturdy cold tolerance is exactly why it flourishes as a perennial all through zones 4 to 9.
Humidity
Everyday outdoor humidity suits it just fine, so there is no number you need to fuss over. Good air movement counts for far more, since still, crowded growth opens the door to powdery mildew and stem rot.
Feeding
Offer a balanced fertilizer in spring as new growth begins, then on through the season. Pause while the plant is flowering, and keep nitrogen light, since too much encourages soft growth that wilt finds easy to take hold of.
Pruning
Prune according to its bloom group, because cutting the wrong type at the wrong moment will cost you flowers. Group 1 old-wood bloomers want only a gentle trim straight after flowering, Group 2 large-flowered hybrids take 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 seldom needs repotting and would rather you leave its roots alone. Only move it when you see roots circling or pushing out of the pot, growth that has stalled, or soil that dries out far too quickly.
Size & spacing
A grown vine reaches 8 to 12 feet (2.4 to 3.7 m) tall and fans out 2 to 6 feet (61 to 183 cm) wide. Give it that breathing room and a support to twine through so air can flow freely around the leaves.
When to plant
Spring or early fall is the moment to plant clematis, while the soil is easy to work and the weather stays gentle. Tuck it in deep, with the crown an inch or two below the surface, and it will root in comfortably before the heat or cold arrives. Look for your first flowers in late spring to early summer, often followed by a second flush later on, and try not to worry if it takes its time settling in.
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
Nearly all clematis hiccups turn up on the stems and leaves, from a shoot that flops overnight to a powdery film across the foliage. The encouraging part is that catching these early usually lets you trim the problem out before it travels. Find what matches your plant below, then act while your help still counts, knowing most setbacks here are recoverable.
One shoot suddenly flops and goes black as the buds open
Take a breath, because this looks worse than it is. When a single shoot drops and darkens right as the buds or flowers appear, while everything else stays green, you are most likely seeing clematis wilt, a fungal stem rot. Check down low near the soil line for dark lesions on the stem. Snip every troubled stem back to clean, healthy tissue or even below ground, wipe your pruners clean between cuts, and keep the watering steady. If you planted with the crown a couple inches deep, your vine very often pushes up fresh growth 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
Young shoots chewed into ragged holes, with shiny trails nearby
Ragged holes and nibbled young shoots on a freshly planted vine usually point to slugs and snails, and the silvery slime trails they leave give them away. No trails in sight? Step out after dark and look for earwigs tucked down in the flowers and crevices. Scatter iron phosphate bait near your young plants, tidy up debris and shady hiding spots, and set out rolled cardboard to catch 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
A dusty white film over leaves that are curling and staying small
If the tops of the leaves carry a powdery white coating and the foliage looks shrunken or twisted, you are dealing with powdery mildew, and it loves still, crowded air. To be sure, rub a leaf: real mildew stays put and the leaf is misshapen, unlike ordinary dust that brushes away. Pull off the leaves that are affected, open the vine up so air can move through, and try to keep water off the foliage. Should it keep spreading, a labeled fungicide used early in the trouble will help you get ahead of it.
Fix:
- Remove affected leaves
- Improve airflow by thinning and proper spacing
- Avoid overhead watering
- Apply a labeled fungicide early in infection if needed
Tender new growth turns sticky and packed with tiny soft bugs
When you spot little soft green or dark bugs huddled on the shoot tips, plus a sticky film and maybe some sooty mold or ants, that is aphids helping themselves to your fresh new growth. Flip over a few young leaves to confirm it. A light visit washes off with a plain spray of water, and for more you can apply insecticidal soap every 5 to 7 days for about 3 rounds. Hold a systemic insecticide in reserve for the heavy, stubborn cases only.
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 is not one to eat, and it is best kept out of easy reach of pets. Every part holds protoanemonin, an irritant that forms once the leaves or stems are chewed or crushed, and the ASPCA lists the vine as toxic to cats, dogs, and horses. The bitter taste does keep most animals from eating much, which is reassuring, but the sap can still sting skin and mouths, so a gentle, careful approach goes a long way.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
A cat that nibbles the leaves or stems may start drooling and have vomiting and diarrhea, along with a sore, irritated mouth. Happily, the bitter, acrid taste tends to put a cat off before it swallows enough to cause real trouble.
Dogs Mild
If a dog chews on the foliage, expect some drooling, gagging, and an unsettled stomach with mouth irritation. That sharp flavor keeps most dogs from swallowing much, which is why serious poisoning is uncommon.
Horses Mild
A horse that grazes the plant may salivate heavily, lose interest in feed, and show oral blistering with colicky discomfort. The good news is that horses usually steer clear of the bitter foliage whenever better forage is around.
Rabbits Caution
That same protoanemonin which bothers cats and dogs will also irritate a rabbit's mouth and gut, so think of the vine as off-limits and fence it away from runs and hutches.
Livestock Caution
Cattle, goats, and sheep can end up with mouth and digestive irritation if they browse clematis, though the acrid taste keeps most of them away unless pasture runs short. To be safe, keep the vine out of reach of grazing stock.
Birds Caution
Because the sap irritates, clematis is a poor pick around pet birds and poultry, so keep curious beaks from pecking at the foliage and stems.
People Caution
No part of this plant is meant for eating, and the sap can redden and blister skin or sting the mouth where it touches. Slip on gloves before you prune and wash up afterward, and keep small children from putting the leaves in their mouths.
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 stretches to hundreds of species and cultivars, but a handful keep showing up in gardens for good reason. These are the ones worth getting to know by name, along with the bloom group each one belongs to, so you will know just how to prune them.
Jackmanii
A beloved old hybrid known for big, deep velvety-purple flowers, this one sits in Group 3, so it blooms on new wood and welcomes a hard cutback every late winter.
Nelly Moser
This Group 2 large-flowered hybrid opens pale pink petals, each striped with a deeper carmine bar, and because strong sun washes those colors out, a spot with some shade suits it best.
Henryi
Strong-growing and reliable, this Group 2 large-flowered hybrid unfurls big creamy-white flowers that are beautifully set off by dark anthers.
Sweet autumn clematis (Clematis terniflora)
Late in the season it covers itself in small fragrant white flowers, yet it self-seeds so freely and has become so invasive across parts of the eastern US that it is best left out of gardens.
Clematis montana
An eager early species that puts on masses of small spring flowers, this Group 1 type asks for only a light trim, and only once it has finished blooming.
How to propagate
Clematis takes its time multiplying, yet it is far from difficult, and the friendliest methods simply copy a plant you already love rather than starting from seed.
LayeringEasy
Spring to summer · A few months to a year
Layering is the surest, gentlest way to grow more clematis. Through spring and summer, pin a low, bendy stem down onto the soil and leave it to root where it rests against the ground, then separate the new plant once it has taken hold over the next few months to a year.
Stem cuttingsModerate
Late spring to early summer · Several weeks to months
Between late spring and early summer, snip semi-ripe internodal cuttings from the current season's growth. Rooting unfolds over several weeks to a few months, and while it asks for a bit more attention than layering, it is well within reach.
DivisionModerate
Early spring · A season
In early spring you can lift and split an established crown, going gently since clematis dislikes having its roots roughly disturbed. Allow the divisions a full season to find their footing before they really get going.
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 lists as toxic to cats, dogs, and horses. A pet that chews it may end up drooling, vomiting, with diarrhea and a sore mouth. The bitter taste usually limits how much an animal eats, yet the vine is far from harmless.
All clematis should be pruned hard every late winter.
The right cut depends completely on the bloom group, so there is no single rule to memorize. Group 1 flowers on old wood and only asks for a light trim after blooming, the Group 2 large-flowered hybrids want a light prune, and only new-wood Group 3 gets the hard cutback. Cut an old-wood type to the ground and you remove that year's flowers.