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Clematis Care: Sun, Planting Depth and Pruning Groups

Clematis care: sun on top and shade on the roots, plant the crown 1 to 2 inches deep, prune by group, mulch 2 to 4 inches and know the wilt. Toxic to dogs and cats.

Iris BellPublished Oct 25, 2026 · Updated Oct 25, 2026 · 3 min read
A violet clematis flower with pointed petals and a reddish center among green leaves
Photo: Didier Descouens, CC BY-SA 4.0

Clematis gets its best flowers with its top in full sun and its roots in cool shade, and it is pruned by group, not by calendar. Clemson describes clematis as mostly woody, deciduous vines with great variety in flower form, color, bloom season and height, and says they need at least 6 hours of sun to flower best. Plant the crown one to two inches below the soil in well-drained soil, mulch the roots, and find out which of the three pruning groups your plant belongs to before you cut. ASPCA lists clematis as toxic to dogs, cats and horses.

Origin
Asia
Sun
At least 6 hours (Clemson); roots shaded and cool
Soil
Well-drained; compost or leaf mold to hold moisture
Planting depth
Crown 1–2 in. below soil level
Mulch
2–4 in. layer, 4–6 in. from the stem (Illinois)
Pruning
By group: after bloom, or Feb–March
Pets
Toxic to dogs, cats, horses (ASPCA)

Sun and soil

Sun

Clemson says clematis need at least 6 hours of sun to flower best. Chicago Botanic Garden describes the ideal as a site where the top of the plant receives full sun and the roots are shaded and cool.

Soil

Well-drained soil is essential (Chicago Botanic Garden). Compost or leaf mold can be added to help retain moisture. Clematis do not like wet feet, especially in winter.

Mulch

Illinois Extension says to apply a 2 to 4 inch layer of mulch, kept about 4 to 6 inches from the stem. Chicago Botanic Garden says a two- to three-inch layer helps retain moisture.

Support

Clemson says clematis are excellent on trellises, fences and walls, and that their dense leaf mat is ideal for shading porches.

How to plant clematis

  1. Pick the spot carefully. Chicago Botanic Garden says clematis do not like their roots disturbed and do not transplant well, so choose the site before you dig.
  2. Prepare well-drained soil. Add compost or leaf mold to help hold moisture (Chicago Botanic Garden).
  3. Set the plant deep. Illinois Extension suggests setting the plant so the first two sets of leaf nodes are underground. Chicago Botanic Garden says one to two inches below the soil level.
  4. Mulch the roots. Apply 2 to 4 inches of mulch, kept 4 to 6 inches from the stem (Illinois Extension), so the roots stay cool and moist.

The three pruning groups

Pruning is where most clematis questions come from. Clemson sorts clematis by when they bloom, and the right cut depends on the group.

Group Blooms What to do Source
Group 1 Early spring, generally April and May, from buds produced the previous year Prune after bloom. In spring remove only dead wood. Clemson, Illinois Extension
Group 2 — Prune in February or March Clemson
Group 3 — Cut each stem to about 2 to 3 feet in February or March Clemson

If you do not know the group, check the plant tag or the cultivar name first. Group 1 blooms from buds produced the previous year (Clemson), so a hard cut in February or March would remove them.

For the full cut-by-cut breakdown, including how to tell your group and what to do if you cannot, see our clematis pruning guide.

Feeding

The sources differ. Illinois Extension suggests a balanced fertilizer once a year, after first bloom for groups 1 and 2 and after pruning in spring for group 3. Chicago Botanic Garden says fertilizing clematis is not necessary.

Clematis wilt

Wilt is a fungal stem rot Clemson says the two fungi credited with causing clematis wilt are Phoma clematidina and Ascochyta clematidina. Cut off and destroy all the affected parts. Small-flowered species are less susceptible to wilt.

Are clematis safe for pets?

ASPCA lists clematis as toxic to dogs, toxic to cats and toxic to horses. The toxic principle it names is an irritant. Keep vines where pets cannot chew them, or choose another vine for a pet area.

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Frequently asked questions

How much sun does clematis need?

Clemson says clematis need at least 6 hours of sun to flower best. Chicago Botanic Garden says to site it so the top of the plant receives full sun and the roots are shaded and cool.

How deep do you plant clematis?

Illinois Extension suggests setting the plant so the first two sets of leaf nodes are underground. Chicago Botanic Garden says the crown is planted one to two inches below the soil level.

When do you prune clematis?

It depends on the group. Clemson says group 1 blooms early on last year's growth and is pruned after bloom, group 2 is pruned in February or March, and group 3 is cut to about 2 to 3 feet in February or March.

Do you need to fertilize clematis?

The sources differ. Illinois Extension suggests a balanced fertilizer once a year, after first bloom for groups 1 and 2 and after spring pruning for group 3. Chicago Botanic Garden says fertilizing clematis is not necessary.

Is clematis toxic to pets?

ASPCA lists clematis as toxic to dogs, cats and horses, with an irritant as the toxic principle.

Sources

  1. Clematis, Clemson Home & Garden Information Center
  2. Clematis, University of Illinois Extension
  3. Clematis (Home, Kitchen and Master Gardener guide), University of Illinois Extension
  4. Caring for Clematis, Chicago Botanic Garden
  5. Clematis, ASPCA Animal Poison Control
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