Clematis
If you want a hardy flowering vine with gorgeous flowers that will showcase your decorative trellis, then Clematis is the plant for you. These hardy vining perennials are incomparable for providing glorious flowers (followed by decorative seedheads) for a vertical space.
Provide Support
Most Clematis plants grow to about 6’ in height, although there are exceptions that are both shorter and taller. They climb by twining around slender supports, so a trellis or lattice will be necessary if you want them to climb a flat or wide surface such as a wall or mailbox post. There are also a few, referred to as bush Clematis, that do not vine at all. Bush Clematis can either be grown within a decorative support structure such as an open frame obelisk or allowed to ramble throughout neighboring plants.
Keep the Roots Cool
For best flower production the top of the vines should receive at least 5 hours of sun a day. However, it is best if the base of the plant is protected from the sun as Clematis roots prefer to be cool and moist. Organic mulch around the base of the plant will help keep the soil around the root zone cool and moist.
Pruning
How and when to prune depends on the type of Clematis and the bloom time.
Clematis are divided into three pruning divisions:
Division 1: Spring Blooming Varieties (bloom on old wood)
These varieties produce flowers on the growth from the previous season. Little to no pruning is necessary for Clematis in this group. After blooming any broken or dead stems can be removed. If more drastic pruning is desired, cut healthy stems back halfway to an active set of buds.
Division 2: Reblooming Varieties (bloom on old & new wood)
This group blooms in early to mid-summer on the previous season’s stems and then again in mid to late summer on new growth. As with Division 1, this group should only be minimally pruned. Dead or broken stems can be pruned out in early spring and crossed and tangled stems removed. If a plant from this group is severely pruned in spring it will not produce the first round of flowers but will still produce the later flowers that are borne on the current season’s growth.
Division 3: Summer Blooming (bloom on new wood)
Clematis in this group bloom mid to late summer on new growth. To encourage strong new growth plants in this Division can be severely pruned, to within twelve inches of the ground, in late winter/early spring before new growth begins.
Clematis we will be growing in 2025 season, by pruning division:
Division 1 (requires no pruning)
- Blue Dancer
Division 2 (minimal pruning)
- Bees Jubilee
- Cardinal Wyszynski
- Guernsey Cream
- N Thompson
- Multi Blue
- Niobe
- Perrins Pride
- Pink Champagne
- Ramona
- Silver Moon
- Snow Queen
Division 3 (can be pruned severely in early spring)
- Comptesse de Bouchard
- Jackmanii
- paniculata/terniflora
- Roguchi
- Stand By Me
Clematis Wilt
Clematis wilt is a fungal disease, specific to Clematis, that causes rapid top dieback. The fungus (Ascochyta clematidina) enters the plant through injured stems and causes rapid wilting from the top down. The fungus kills the top growth of the plant but does not kill the roots, so cutting the stems down to ground level may allow your plant to resprout from the base and recover. Dispose of infected stems to remove fungal spores that may re-infect your plant. Large flowering varieties are most susceptible, as are plants that are stressed by lack of water. Selecting small flowering or species Clematis and keeping the roots moist and cool will reduce the occurrence of Clematis wilt.
Clematis in a Nutshell
- Mature height: 4’-20’, depending on variety (majority are 5’-8’)
- Mature spread: 2′-6′
- Growth form: Twining vines that require a structure with supports small enough to twine around. Some are also non-twining.
- USDA Hardiness Zones: 4
- Flowers: Most produce large outfacing flowers in a range of forms and sizes in summer. There are also a few that have smaller flowers and some that bloom in spring and in fall.
- Light requirement: Full Sun to Partial Shade. Prefer sun on their heads and shade on their feet.
- Water Requirements: It is important to keep newly planted Clematis well-watered, and even established plants should not be allowed to go completely dry.
- Growth Rate: Fast
- Maintenance: Annual pruning, if desired (see above)
- Especially valuable for:
- Bringing very showy flowers to a vertical space
By Zannah Crowe
