Jack Frost


Denomination: 'Jack Frost'
Botanical Name: Brunnera macrophylla
Applicant/Holder: Walters Gardens, Inc.
1992 96th Avenue
P.O. Box 137
Zeeland, Michigan
United States of America
Breeder: John D. Walters, Walters Gardens, Inc., Zeeland, United States of America
Agent in Canada: Variety Rights Management
475 County Road 18
R.R. #2
Oxford Station, Ontario
K0G 1T0
Tel: 613-258-9015
Application Date: 2000-05-10
Application Number: 01-2709
Grant of Rights Date: 2004-05-17
Certificate Number: 1799
Grant of Rights Termination Date: 2022-05-17

Variety Description

Variety used for comparison: 'Langtrees'

Summary: 'Jack Frost' has a slightly longer leaf than 'Langtrees'. The apex of the leaf in 'Jack Frost' is acute to acuminate in shape while in 'Langtrees' it is acute. The variegation of the upper side of the leaf blade in 'Jack Frost' is silver/grey and covers all the surface area except the veins and margin while in 'Langtrees' the variegation is speckles of silver/grey which are found towards the apex and edges of the leaves covering much less surface area.


'Jack Frost' is a vegetatively propagated perennial brunnera variety which has a growth habit that is both upright-bushy and arching forming a mound shaped clump. There is a sparse degree of branching. The striated stem is medium in thickness, with dense pubescence, a medium green colour, and no anthocyanin or waxy bloom present. The simple leaves are reniform in shape, and arranged in a rosette fashion. The leaf blade has an acute to acuminate shaped apex and a cordate shaped base with a margin that is entire. There is no waxy bloom on the upper side of the leaf blade but there is dense pubescence on both the upper and lower sides. The main colour of the upper side of the variegated leaf blade is a silver grey with the secondary light green colour being found along the veins and edge. There is a petiole.

'Jack Frost' flowers once early in the season for a short length of time. The inflorescence is a cyme type that bears erect florets in the terminal position. The rounded shaped petals of the florets are touching, and very few in number. The petal has an obtuse shaped apex, and has no pubescence on the upper side. 'Jack Frost' has light blue coloured florets.

Origin & Breeding History: 'Jack Frost' is a non induced sport of the variety 'Langtrees'. It was discovered in a batch of tissue cultured plants in the spring of 1997 in the greenhouses of Walters Gardens Inc. in Zeeland, Michigan, United States of America. The plant was separated and continually evaluated under greenhouse conditions at the same nursery. In the spring of 1998 the plant was divided into two pieces by dividing the crown. On June 3, 1999 following further evaluation the plants were propagated in tissue culture. 'Jack Frost' was selected on the basis of its intense silver colouration on the upper side of the leaves, with offsetting green colouration along the veins and edge giving it a cracked porcelain like appearance.

Tests & Trials: The trials were conducted in the summer of 2003, at Oxford Station, Ontario. There were ten plants of each grown in a field with plants spaced 0.45 metres apart.

Comparison tables for 'Jack Frost' with reference variety 'Langtrees'

Leaf blade length (cm)

  'Jack Frost' 'Langtrees'
mean 15.27 13.40
std. deviation 4.75 2.15

Leaf blade width (cm)

  'Jack Frost' 'Langtrees'
mean 12.23 12.27
std. deviation 1.16 2.02
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