Denomination: 'Tweety'
Botanical Name: Coreopsis verticillata
Applicant/Holder: van der Spek, Bram
Castor 2, 2743 MB
Breeder: Bram van der Spek, Waddinxveen, Netherlands
Agent in Canada: BioFlora Inc.
38723 Fingal Line
R.R. #1
St. Thomas, Ontario
N5P 3S5
Tel: 519-631-6241
Application Date: 2011-07-27
Application Number: 11-7339
Grant of Rights Date: 2013-10-01
Certificate Number: 4641
Date rights surrendered: 2015-10-01

Variety Description

Variety used for comparison: 'Zagreb'

Summary: The plant of 'Tweety' is shorter than the plant of 'Zagreb'. The stem of 'Tweety' is thin while the stem of 'Zagreb' is medium in thickness. The flower of 'Tweety' is smaller in diameter than the flower of 'Zagreb'. The ray floret of 'Tweety' is shorter and narrower than the ray floret of 'Zagreb'.


PLANT: upright bushy growth habit, very dense branching
STEM: light green, absent or very weak anthocyanin colouration, very sparse pubescence, thin, smooth to weakly ribbed

LEAF: medium number of leaflets, linear, acute apex, sessile base, margin deeply divided, absent or very sparse pubescence on upper and lower side, upper side meduim green with weak glaucosity, lower side light green, no variegation, no petiole

PEDUNCLE: absent or very weak anthocyanin colouration, absent or very sparse pubescence
FLOWER: erect attitude
RAY FLORET: medium number, open to touching, straight along longitudinal axis, elliptic, apex dentate, absent to very weak recurvature of tip, absent to very sparse pubescence on lower side, upper side yellow (brighter than RHS 9A), lower side yellow (RHS 9A).

Origin & Breeding History: The variety 'Tweety' originated from an open pollination between two unknown Coreopsis verticillata plants, conducted in Boskoop, Netherlands in 2005. The initial selection of 'Tweety' was made in 2007, based on its smaller flowers and compact mounding growth habit. Asexual propagation since that time has been through the use of vegetative cuttings.

Tests & Trials: Trials for 'Tweety' were conducted in a polyhouse during the summer of 2012 in St. Thomas, Ontario. The trial included a total of 20 plants each of the candidate and reference varieties. All plants were grown from rooted cuttings and transplanted into 15 cm pots on May 14, 2012. Observations and measurements were taken from 10 plants of each variety on July 12, 2012. All colour determinations were made using the 2007 Royal Horticultural Society (RHS) Colour Chart.

Comparison tables for 'Tweety' with reference variety 'Zagreb'

Plant height (cm)

  'Tweety' 'Zagreb'
mean 27.2 37.8
std. deviation 2.07 4.40

Flower diameter (cm)

  'Tweety' 'Zagreb'
mean 2.7 4.0
std. deviation 0.32 0.15

Ray floret length (cm)

  'Tweety' 'Zagreb'
mean 1.3 2.1
std. deviation 0.07 0.09

Ray floret width (cm)

  'Tweety' 'Zagreb'
mean 0.5 0.9
std. deviation 0.04 0.07

Click on image for larger view
Coreopsis: 'Tweety' (left) with reference variety 'Zagreb' (right)

Click on image for larger view
Coreopsis: 'Tweety' (left) with reference variety 'Zagreb' (right)

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