Denomination: 'Thusid1'
Botanical Name: Thuja occidentalis
Applicant/Holder: Sidhu, Gurjit
9623 Sylvester Road
Mission, British Columbia
V2V 7K6
Breeder: Gurjit Sidhu, Mission, British Columbia
Application Date: 2009-07-09
Application Number: 09-6681
Protective direction granted: 2009-07-09
Grant of Rights Date: 2011-08-19
Certificate Number: 4117
Grant of Rights Termination Date: 2029-08-19

Variety Description

Variety used for comparison: 'Smaragd' (Emerald)

Summary: The colour of the newly opened leaf in the spring is light yellow at the tip and light green at the base for 'Thusid1' while the leaf of 'Smaragd' is dark green.


PLANT: narrow pyramidal shape, dense foliage, medium green colour group
BRANCH: dense, erect attitude, flexible, reddish brown

SPRAY: second order branchlets medium to dense, stem medium green with yellow towards base, third order branchlets medium to dense with medium green stem colour and absent to very weak anthocyanin colouration, fourth order branchlets sparse to medium in density

LEAF: arranged in opposite pairs around the axis of the branchlet, scale like, appressed, acute apex, entire margin, margin with involute fold, upper side of newly opened leaf in spring light yellow (RHS 10B) at tip and light green (RHS N144D) at base, previous seasons leaves dark green (RHS N137D) on upper side and dark green (RHS 143B-C) on lower side in spring, leaves in summer dark green (RHS 137A) with light green (RHS 144C-D) at tips on upper side, lower side dark green to brown green (RHS 137A-B).

Origin & Breeding History: The variety 'Thusid1' originated as a whole plant mutation of the variety 'Smargd'. The mutation was discovered in April, 2006 in Mission, British Columbia, Canada. The new variety was selected based on the yellow colour of the tips of new foliage. Propagation by stem cuttings was first conducted in winter of 2006.

Tests & Trials: Trials for 'Thusid1' were conducted in an outdoor irrigated container trial during the spring and summer of 2010 in St. Thomas, Ontario. The trial included a total of 10 plants of the candidate variety and 8 plants of the reference variety. All plants were grown from bare root plants planted into 1 gallon containers on February 24, 2010. Observations and measurements were taken on July 15, 2010 with the exception of the early spring observations which were made on April 6, 2010. All colour determinations were made using the 2007 Royal Horticultural Society (RHS) Colour Chart.

Comparison table for 'Thusid1' with reference variety 'Smaragd'

Colour of newly opened leaf in spring (RHS)

  'Thusid1' 'Smaragd'
upper side 10B at tip, N144D at base 144A

Click on image for larger view
Cedar: 'Thusid1' (left) with reference variety 'Smaragd' (right)

Click on image for larger view
Cedar: 'Thusid1' (left) with reference variety 'Smaragd' (right)

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