Clematis Vines

Types of Clematis

There are three basic types of clematis; ones that produce flowers on this year’s growth (new wood); ones that produce flowers on the previous year’s growth (old wood); and those that produce flowers on both new and old growth.  Knowing the variety you have is essential in order to know the proper pruning technique.   (see below)
Clematis 'Jackmanii'
Clematis 'Killian Donahue'
Clematis 'Comtesse de Bouchard'
Clematis

Location

Clematis require a site that will receive at least 6 hours of sun or more per day.  This helps in bud and bloom production, and in lowering susceptibility to crown rot.  Young Clematis are extremely susceptible to crown rot, which is a disease.  Crown Rot can usually be prevented by planting the Clematis in well-drained soil.

The plants are also susceptible to any root disturbances. These can include animals digging around the roots, or growing in a low spot where water may collect.  Plant the vine somewhat deep so that 2 of the buds are below ground level so that they will be preserved in case of dieback of the vine.  Clematis also like to have a cool root zone.  Place a layer of mulch (not exceeding 1½”) around the base of the plant or plant clematis by shrubs, perennials, or annuals that will shade the root system

Planting

  • Dig a hole 15″ wide by 18″ deep
  • Fill the hole with water several times to check for good drainage.  Clematis do not like “wet feet”.
  • Amend the soil with Sweet Peet.  Create a 1:1 ratio of Sweet Peet and regular garden soil or topsoil.
  • Heavy clay soil can benefit from sharp gravel being added to the mixture (or oyster shell poultry food)
  • A pinch (1/8 cup) of 0-46-0 phosphate is also helpful to mix into the planting soil.
  • Prune the plant back by half before planting.
  • To encourage a vigorous crown, plant a Clematis at a 45-60 degree angle to the ground level about one inch deeer than the soil level in the pot.
  • Water well.

Pruning

Knowing the variety you are planting is essential in order to know the proper pruning technique.  Check your plant for either A, B or C and follow the pruning instructions below.

Group A

Early Flowering Clematis

Plants in this group bloom in early spring, generally in April and May, from buds produced the previous season. Prune these back as soon as possible after bloom but no later than the end of July.  This allows time for new growth to produce flower buds for the next season.  Remove shoots that have bloomed.  Do not cut into woody trunks.

Group B

Large Flowered Hybrids

These bloom in mid-June on short stems from the previous season’s growth and often again in late summer on new growth.  Prune in March by removing dead and weak stems, then cut back remaining stems to the topmost pair of large, plump green buds.  This cut could be a few inches to a foot or two from the stem tips.  Prune slowly from the top until you reach a good bud, one stem at a time

Group C

Late Flowering Clematis

Plants in this group should be cut back in early March to the first set of two strong buds on each stem which is usually 1-3’ above ground level.  You basically want to cut right above the place where the new season’s growth begins. This will include removal of some good stems and buds but don’t worry, they’ll grow back!

Watering

Clematis need water, but not too much.  Feel the soil between waterings.   Plant that are too wet can be affected by crown rot.  How often clematis need to be watered will depend on the weather

Fertilizing

Clematis are heavy feeders.   After the vine is established, use fertilizer recommended for flowering plants, such as Plant-tone or a time-release fertilizer.  Clematis will also benefit from an annual top dress of rich compost. 

Clematis Wilt

Clematis wilt is one of the greatest misnomers in the care of Clematis.  When you see symptoms such as sudden stem collapse with the stems and leaves turning brown or black in just a few days, you more then likely have a slug problem. Small, almost  invisible slugs feeding on Clematis stems will cause symptoms similar to Clematis Wilt.  A slug bait such as Sluggo placed around the plant starting in May will prevent slug damage

Growing Tips

  1. Choose a favorable planting site. Your site should receive about 6 hours of sun or more per day and be well-drained with a neutral pH.
  2. Select resistant plants.  Small-flowered hybrids seem to be more resistant than large-flowering forms.
  3. To encourage a vigorous crown, plant a Clematis at a 60 degree angle to the ground level.
  4. Keep the area around your Clematis free of debris all year round.
  5. Take special care to avoid injury to the stem and roots.
  6. Do not cultivate near the roots of Clematis.
  7. Mulch the root system as they like to have their roots shaded.
  8. Remove diseased stems immediately.  In the event that the plant becomes infected, cut the diseased stems just below ground level and destroy them.