Four Star Culture Guide - 2019 - 80

CLEMATIS
ZONE HARDINESS
4 - 9 (5 - 9 Happy Jack® Purple)

VERNALIZATION
A cold treatment is required on Clematis.

NUTRITION
pH: 5.8 - 6.2
EC: (2:1 extraction method) 0.6 - 0.9
Low fertilization is recommended. 100ppm - 150ppm N

PLANTING
Clematis perform best when planted in a well-drained, porous
growing medium.

TEMPERATURE for forcing from liners
Forcing/Growing on: 58 F Night- 66 F Day
Holding: 40 F Night - 50 F Day
If the plants are started too warm, top growth will outpace
root development. Run cool to match development speeds.
Once plants reach a saleable size, they can be moved to a frost
protected open environment with good air movement.
WATERING
Moderate to Moist: Best if planted in well-drained soil. Water
thoroughly without oversaturating, keep moist during root
development, allow soil surface to dry before watering after the
crop is rooted to the edge of the pot.
TIMING
28 Liner to True 1 Gallon: 8 - 10 weeks with one plug per
container. A typical planting date for spring forcing would be
Week 10 for finishing in Week 18 - 20. If a larger size is desired,
we recommend planting these in the fall and doing additional
bulking prior to dormancy. Planting a 28 count liner into a 2 - 3
gallon and bulking in the summer is also a great way to finish a
larger high-quality spring crop.

When growing shrubs we recommend using an aged or
composted pine bark-based media as opposed to an annual
growing mix that traditionally tend to be heavier in peat. Bark
adds weight and stability to the growing mix and tends not to
compress and shrink over time thus adding the longevity that
can be needed on long-term crops such as shrubs.
LIGHT/LIGHTING
During early spring forcing, plants should be given as much light
as possible. Crops should be grown on a trellis and spaced such
that they do not intertwine.
TRIMMING/PINCHING
Depending on the variety, Clematis will bloom on new wood,
old wood or both. A crop grown on a trellis or other support
structure will need little additional pruning, but can be trimmed
back to stay within bounds of a trellis system.
Flowering
Wood

Flower Timing
Late Summer/
Early Fall

Prune lightly in
spring leaving 3'

'Viva Polonia',
'Sweet Summer
Love'

Old and
New

Late Spring/Early
Summer

Prune in early
spring as new
growth begins
(18" - 24") leaving
at least 2 of the
most healthy
buds

Brother Stefan®,
Happy Jack®,
Madame Maria®,
Pink Mink®

GROWTH REGULATORS
Trimming and pruning are used mostly on Clematis to control
plant height. Cultural practices such as good air movement in
an open environment can help control plant height and assist in
finishing a high-quality crop.

Four Star Greenhouse I www.pwfourstar.com I 734-654-6420
80

Varieties

New

Quick Turn™ Liner to True 1 Gallon: 6 - 8 weeks with one
plug per container. A typical planting date for spring forcing
would be Week 12 for finishing in Week 18 - 20.
Quick Turn Liner to 2 - 3 Gallon: Planting a Quick Turn liner
into a 2 - 3 gallon container and bulking in the fall is also a
great way to finish a larger high-quality spring crop.

Prune

The rates and chemicals listed are based on our southeast Michigan growing conditions, and are not recommended for nationwide application.
Please adjust the rates and spray applications to your location and facility.

http://www.pwfourstar.com

Four Star Culture Guide - 2019

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