Radslam

Rose

Variety Description

Variety used for comparison: 'Radral' (Coral Knock Out)

Summary: The leaf of ‘Radslam' is narrower than that of ‘Radral'. The flower of ‘Radslam' has a smaller diameter and a greater number of petals than that of ‘Radral'. The petal on the flower of ‘Radslam' has weak reflexing of the margin, weak undulation and is shorter than that of ‘Radral', which has a medium degree of reflexing of the margin and a medium degree of undulation. When mature, the inner side of the petal of ‘Radslam' is orange red with medium yellow towards the base and darker medium yellow at the base while that of ‘Radral' is red pink to pink with light orange towards the base.

Description:

PLANT: shrub growth type, very weak intensity of anthocyanin colouration on young shoot

STEM: medium number of greenish prickles

LEAF (UPPER SIDE): medium green, weak to medium degree of glossiness
LEAFLET: absent or very weak undulation of margin
TERMINAL LEAFLET: ovate shape, obtuse base, acuminate apex

FLOWER: double type, orange colour group, irregularly rounded shape, flattened convex profile of upper part, flattened convex to convex profile of lower part, medium fragrance, weak sepal extensions
PETAL: no reflexing of petals one-by-one, obovate and obcordate shape, absent or very weak incisions, weak reflexing of margin, weak undulation
PETAL (INNER SIDE): two colours, orange red (RHS 41B) with medium yellow (RHS 4B) towards base and medium yellow (RHS 7A) at the base when mature, light blue pink (RHS 55C-D) with white (RHS N155B) at base when aged
PETAL BASAL SPOT (INNER SIDE): very small, medium yellow
PETAL (OUTER SIDE): pink to light red pink (RHS 39B-C) with light yellow (RHS 3D) at base
OUTER STAMEN: predominantly medium yellow filamen

Origin & Breeding History: 'Radslam' originated from a controlled hybrid cross conducted between the female variety 'Radhope' and the male variety ‘Wekvossutono' in June 2015 in Milwaukee, Wisconsin, United States. From the resulting progeny, the new variety was selected based on flower colour, plant vigour, growth habit, and disease resistance in September 2016. ‘Radslam' was first propagated asexually by cuttings in September 2016 in West Grove, Pennsylvania, United States.

Tests & Trials: The comparative trial for ‘Radslam' was conducted outdoors during the summer of 2024 at Bioflora Inc., in St. Thomas, Ontario. The trial included a total of 9 plants of the candidate variety and 10 plants of the reference variety. All plants were grown from bare-rooted plants transplanted into 11.4 liter containers in summer 2023. Observations and measurements were taken from 10 plants, or parts of plants, on June 16, 2024. All colour determinations were made using the 2015 Royal Horticultural Society (RHS) Colour Chart. Mean differences were significant at the 5% confidence probability level based on a paired Student's t-test.

Comparison tables for 'Radslam' with reference variety 'Radral'

Leaf width (cm)

Number of petals per flower (count)

Flower diameter

Petal length (cm)

Main colour of the inner side of the petal (RHS)

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Rose: ‘Radslam' (left) with reference variety ‘Radral' (right)

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Rose: ‘Radslam' (left) with reference variety ‘Radral' (right)

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Rose: ‘Radslam' (left) with reference variety ‘Radral' (right)