Growing Clematis in Iowa

Clematis are vining members of the buttercup family (Ranunculaceae). Over 250 species and hundreds of varieties are available which bloom from May until frost. No matter how you say it (kla-MAT-us; KLEM-a-tis), they are some of the most beautiful and diverse climbing vines for the landscape. They have earned the moniker of "Queen of Vines."

clematis on mailbox
Clematis are beautiful additions to the landscape. (1)

Description  |  Types  |  Flowering Groups  |  Growing Conditions  |  Planting  |  Care  |  Support  |  Pruning  |  Propagation  |  Cut Flowers  |  Potential Problems  |  Recommended Species & Cultivars  |  More Information

The colorful portion of the flowers is made up of sepals instead of petals. Flowers may be single or double. Flower form varies from nodding, pitcher-shaped, bell-shaped, or star-shaped to the familiar large, flat, erectly held blossoms. The petal-like sepals may be thin, wide, pointed, rounded, crinkled, twisted, or even crimped. They may be marked with center bars, stripes, or vivid shadings. Flowers may have contrasting colored stamens or no stamens at all. They are found in many colors, often pinks, purples, blues, lavenders, and whites. Small-flowered species offer a range of fragrances from almond to hot cocoa (unfortunately, the large-flowered varieties often lack fragrance).  Clematis seedheads are also attractive, forming silvery, feathery, and fluffy tufts.  Foliage ranges from medium to dark green. Many have entire leaves; however, some species may have serrated or lobed foliage.


Vining Types

Many gardeners are familiar with the vining clematis. Some can grow 8 to 12 feet in a single season; others reach only 2 to 4 feet. Rather than twining or using structures like tendrils or holdfasts, vining clematis climb by twisting their petioles around a support.   

Clematis integrifolia 'Rose Colored Glasses'
Clematis integrifolia 'Rose Colored Glasses' (solitary clematis)  (2)

Bush Types

There are also some non-vining types of clematis.  Referred to as bush or shrub-types these plants act more like perennials in the landscape with their upright and bush-like growth habits. They typically dieback to the ground over winter.  Plants can be anywhere from 12 to 36 inches tall.  Some varieties stand well on their own, and others require support of some kind, whether that be a stake, cage, or nearby plant to lean on.  Some form a tidy, rambling mound in the middle or front of the border, and others can add height and color to the middle or back of the perennial border.  

Flowering Groups

Clematis are divided into three main groups based on the season of bloom. Understanding the group your clematis belongs to is important to know when it will bloom, and when it should be pruned, should that be needed.

clematis alpina By ChrWeiss AdobeStock
Clematis alpina (alpine clematis) (3) 

Spring Blooming (Group 1)

Group one is the earliest to bloom, usually in May.  This group is often the most difficult to grow in Iowa because some varieties may experience winter dieback, which would destroy the flower buds.  These types produce their flowers on short stalks emerging directly from the leaf axil bud on the previous season's stems. 
(Examples: Clematis alpina and Clematis macropetala)

Repeat Blooming (Group 2)  

Henryi by JAG IMAGES AdobeStock
'Henryi'  (4)

The second group of clematis blooms twice. Flowers are produced from May to July on the previous season’s growth. In late summer, plants bloom again on the current year’s growth. The varieties not reliably winter hardy may only bloom once in summer should the previous year's growth dieback in winter. 
(Examples: ‘The President,' ‘Henryi,’ and ‘Ramona’)

Summer & Fall Blooming (Group 3)

The third group of clematis flowers on the current year’s growth. Vines produce one main flush of bloom sometime from late May to September. If left unpruned, they begin growth from where they flowered the previous season and become bare at the base with flowers only at the top. Because they bloom on current year’s growth, these are the most reliable performers in Iowa. 
(Examples: Clematis viticella, Clematis terniflora, and large-flowered hybrids such as 'Jackmanii,' ‘Ernest Markham,’ and ‘Hagley Hybrid’) 

sweet autumn clematis
Clematis terniflora (sweet autumn clematis)  (5)

Growing Conditions

Clematis thrive in rich, well-drained soils with at least 6 hours of sunlight each day and 1 inch of water per week. Adding compost or peat to the planting bed before planting can help provide the well-drained but moist organic soils clematis prefer. They grow best in soils with slightly acidic to neutral pH

While plants grow and flower best in full sun, they thrive when the root system is kept cool.  Protect plants from the late afternoon sun.  Covering the soil at the vine's base with mulch or planting other perennials to shade the root zone is beneficial.


Clematis integrifolia
Clematis integrifolia (solitary clematis)  (6)

The best time to plant clematis is early spring. However, containerized plants can be planted throughout the growing season. The crown should be planted an inch below the soil surface to encourage multiple shoots and provide winter protection. If roots are crowded, straighten them out before planting. Water well and mulch with 2 to 3 inches of organic material, such as wood chips or shredded bark.

After planting, trim to 12 inches or a pair of low buds to encourage multiple branching and additional shoots. Plants often have limited above-ground growth the first year or two after planting.  They form deep, extensive root systems and, once established, will grow vigorously.  


Fertilize established plants in spring with an all-purpose garden fertilizer with relatively low numbers.  A 10-10-10 or a 5-10-5 are good options. Avoid fertilizers high in urea and ammonia. 

Clematis require at least an inch of water per week and like their root systems kept cool. Mulching is extremely important. 


clemaits jackmanii By MOLLY SHANNON AdobeStock
'Jackmaii'  (7)

Clematis climb by twisting their petioles or leaf stalks around a support. They can be grown on trellises, fences, lampposts, deck rails, and other structures. Clematis also can be allowed to climb over shrubs, small trees, tree stumps, and rock piles.

When planting, locate the plant near, but not right next to the support (~1-2 feet away). This will encourage the new growth to wind through the support
towards the light.  Most newly planted vines need a little assistance to get started on a trellis or other climbing structure, but once they are established have no problem climbing up and showing off with beautiful blooms.


Pruning appropriately based on the flowering group is important.  Improper pruning will sacrifice blooms.  Pruning can also improve appearance.  Vines commonly form "bare legs," getting woody and sparse at the base.  Additionally, more vigorous types (like sweet autumn clematis) can become messy and overgrown looking without regular pruning.  

Clematis ×durandii (Durand clematis)
Clematis ×durandii (Durand clematis)  (8)

Spring Blooming (Group 1)

Most in this group need very little pruning.  They should be pruned immediately after flowering if they need shaping or trimming.  If they experience winter dieback, prune back to live wood after bud break in spring.

Repeat Blooming (Group 2)  

These types can be more tricky to prune but also more forgiving.  Should you do it improperly, you remove the spring flush of flowers, but it will still get blooms in summer.  In early spring, prune out the dead wood.  Leave behind as much live growth as possible.  If they experience extensive winter dieback, cut vines back to two feet in early spring. (at the expense of the spring flowers!)

Summer & Fall Blooming (Group 3)

Pruning is relatively easy for this group. Vines can be cut back to within 6 to 12 inches of the ground in late winter/early spring. An alternative method is to wait until bud break in spring and prune back to the uppermost pair of strong buds on each stem.  

nelly moser By dola710 AdobeStock
‘Nelly Moser’  (9)

What if I don't know what group my clematis belongs to?

Remember, pruning is not essential.  It can improve the appearance of the vines, but they will still bloom whether you prune them or not.  If you are unsure, you can observe and experiment to determine which group they belong to.  Observe their typical bloom time.  If they bloom first thing in May, they are likely group 1.  If they bloom twice a year, they are likely group 2.  If they only bloom later in the year, they are either in group 3 or group 2 but experienced significant winter damage.

Once you identify the group you suspect they belong to, prune as appropriate.  If you don't get flowers that year, you pruned incorrectly.  Try a pruning method for a different group next year.


Propagation is best done by layering or growing from seed. Large plants can be divided; however, it isn't an easy task.

Clematis seed pods
Clematis seed pods  (10)

Cut Flowers

Clematis are excellent fresh-cut flowers and can last four days or longer. Look for flowers that have just opened or are only three-fourths open on thick, strong stems.  They also form attractive seed heads that can be nice additions to floral arrangements.

Potential Problems

Overall, clematis have few issues and no serious insect pests.  But occasionally, issues may arise.

Clematis Wilt

The only serious diesease issue they face is clematis wilt caused by Asochyta clematidina. Affected vines wilt suddenly and then die. Entire stems may suddenly collapse. Dead vines should be cut at ground level, removed, and destroyed. Clematis wilt rarely kills the entire plant. Affected plants usually send up new shoots. This problem only occurs on large-flower varieties and usually appears just as the flower buds begin to swell.

No Blooms

If flowers don't form, there are several potential causes.  

  • Low light.  While some will tolerate part shade, most prefer to have at least 6 hours of direct sunlight a day to bloom well. 
  • Poor fertilization.  When not fertilized regularly, plants can reduce or stop blooming.  Alternatively, if you apply too much fertilizer, most notably nitrogen, there will be abundant growth and few blooms.
  • Improper pruning.  If plants are pruned too severely at the wrong time, you will remove the flower buds before they have a chance to develop.
  • Winter damage.  Not all clematis are reliably winter hardy in Iowa.  When plants experience significant winter dieback and belong to groups 1 or 2, flowers will be negatively impacted.
  • Immature.  It can take plants up to three years to become established enough in the garden to begin blooming.  
clematis crystal fountain
Clematis ‘Evipo038’ Crystal Fountain™   (11)

Species & Varieties to Grow

There are hundreds of clematis species and cultivars.  Not all clematis are hardy in Iowa, but numerous species and cultivars can be successfully grown in the state.  Below are a few to consider.

Vining Types

  • Clematis alpina (alpine clematis) – blue flowers (group 1)
  • Clematis ×durandii (Durand clematis) – bluish-lavender flowers (group 3)
  • Clematis macropetala (downy clematis) – lavender-blue flowers (group 1)
  • Clematis orientalis (Oriental virginsbower) – yellow flowers (group 3)
  • Clematis terniflora (sweet autumn clematis) – white flowers (group 3) **see note below
  • Clematis texensis (scarlet clematis) –scarlet flowers (group 3)
  • Clematis viticella (Italian clematis) – purple flowers (group 3)
  • ‘Ascotiensis’ – hybrid; blue flowers (group 3)  
  • ‘Bees Jubilee’ – C. patens hybrids;  pink flowers (group 2) 
  • ‘Betty Corning’ – hybrid;  blue flowers (group 3)  
  • 'Comtesse de Bouchaud’ – hybrid; pink flowers (group 3)
  • 'Crystal Fountain (‘Evipo038’) - hybrid; lavender blue flowers (group 2)
  • ‘Duchess of Albany’ – C. texensis; pink flowers (group 3
  • ‘Ernest Markham’ – hybrid;  red flowers (group 3)
  • 'Gipsy Queen’ – hybrid; purple flowers (group 3)
  • ‘Hagley Hybrid’ – hybrid; pink flowers (group 3)
  • ‘Henryi’ – C. patens hybrids;  white flowers (group 2)
  • 'Jackmanii' – hybrid; purple flowers (group 3)
  • 'Jackmanii Alba’ – hybrid;  white flowers (group 3)
  • 'King Edward VII’ – C. patens hybrids; bicolor flowers (group 2)  
  • ‘Lord Nevill’  – C. patens hybrids;  blue flowers (group 2)  
  • ‘Madame Edouard Andre’ – hybrid;  red flowers (group 3)
  • ‘Marie Boisselot’  – C. patens hybrids;  white flowers (group 2) 
  • 'Mrs. Cholmondeley’ – C. patens hybrids;  blue flowers (group 2) 
  • ‘Nelly Moser’ – C. patens hybrids; bicolor flowers (group 2)  
  • ‘Niobe’ – C. patens hybrids;  red flowers (group 2)  
  • ‘Ramona’ – hybrid; blue flowers (group 2)  
  • ‘Rouge Cardinal’ – C. patens hybrids;  red flowers (group 2)  
  • ‘Star of India’ – hybrid; bicolor flowers (group 3)
  • ‘The President’ – C. patens hybrids; purple flowers (group 2) 
  • ‘Ville de Lyon’ – hybrid;  red flowers (group 3)
sweet autumn clematis
Sweet autumn clematis rambling over a shrub and intertwined with morning glory  (12)

Bush Types

  • Clematis integrifolia (solitary clematis) – indigo blue flowers (group 3)
  • Clematis recta (ground virginsbower) – white flowers (group 3)
  • Clematis heracleifolia (tube clematis) - lavender blue flowers (group 3)
  • 'Stand by Me' - hybrid; blue flowers (group 3)

** Sweet Autumn Clematis reseeds readily, and care must be taken to remove seedlings as they appear in the garden.  Removing the flowers after the bloom has finished can help reduce the seed set.  The closely related virgin's bower (Clematis virginiana) is a native alternative but doesn't have the same sweet fragrance.

More Information

Photo credits: 1: Aaron Steil; 2: Aaron Steil; 3: ChrWeiss/AdobeStock; 4: JAG IMAGES/AdobeStock; 5: Cindy Haynes; 6: Cindy Haynes; 7: MOLLY SHANNON/AdobeStock; 8: Cindy Haynes; 9: dola710/AdobeStock; 10: Aaron Steil; 11: Aaron Steil; 12: Aaron Steil

Last reviewed:
May 2024