Patent Grant
PP35081
Genus and species: Acer pseudosieboldianum x Acer palmatum.
Denomination: ‘INAG-E61’.
‘INAG-E61’ is a new and distinct variety of Maple tree. ‘INAG-E61’ originated from a tree breeding program started in 1997 with the goal of expanding the cold tolerance range of Japanese Maple trees to include USDA Zone 4. The focus has been on red foliage color.
The general term “Japanese maples” applies to species, forms, and cultivars within Section and Series Palmata including native Japanese species Acer palmatum, japonicum, shirasawanum, and sieboldianum and two not native species, the West Coast North American species Acer circinatum or Vine maple and Acer pseudosieboldianum or Korean maple.
Acer pseudosieboldianum is the foundation breeding genetics used for enhancing hardiness. This species is native from the Korean peninsula north into the biodiverse forested Ussuri river region of Eastern China and Russia, a region spared from past glaciation enabling long periods of uninterrupted species development from a former warm climate to the current cold dry winter climate. Acer pseudosieboldianum successfully grows in the Upper Midwest region of USDA zone 4 with some seedling and cultivar success in USDA zone 3. Besides hardiness, Korean maple has features of sun tolerant vibrant green summer foliage, outstanding multicolored fall foliage, but as a garden tree the typically marcescent leaves and coarse, open, erratic branching and unpredictable habit is a detraction.
The species native to Japan: Acer palmatum, japonicum, shirasawanum, and sieboldianum have long been garden worthy trees with hundreds of years of human selection and refinement. These species and selected cultivars are USDA Zone 5 or 6 or 7 and as such are either marginal or not hardy as garden trees for much of North America, hence, the breeding combination of superior garden quality Japanese maple trees crossed with the cold hardy genetics from Acer pseudosieboldianum.
In 1997, a controlled breeding program was started in a greenhouse in Boring, Oreg. using Korean maple seedlings (female parent) with Acer palmatum ‘Nuresagi’ unpatented (male parent). ‘Nuresagi’ is an upright Japanese maple tree with deep-purple-red, palmate, 5-7 lobed leaves, and hardy to USDA Zone 5. Seedlings from this cross were grown and evaluated with one seedling designated ‘E7’ showing red pigmented new growth that matures green. ‘E7’ was propagated and later named NORTH WIND ‘Is1NW’ (not patented). This cultivar has been found to be USDA Zone 4 hardy, but the red color needed further improvement. In spring 2006 NORTH WIND ‘Is1NW’ was used as the female seed parent for ‘INAG-E61’ and was open-pollinated. The male parent is unknown but adjacent to the female parent tree were three same-aged, red-leafed hybrid selections identified as ‘E3’, ‘E4’, and ‘E26’. Seeds from the open-pollination were collected Fall 2006 and planted April 2007 and germinated June 2007. The best seedlings from this cross were grown for long term evaluation in a testing location in Boring, Oreg. In July 2016 ‘INAG-E61’ was first identified. First hardiness screening test December 2016.
‘INAG-E61’ was first propagated by grafting in August 2016 onto Acer palmatum seedling rootstock (unpatented). ‘INAG-E61’ reproduces true to type in successive generations of asexual reproduction via grafting onto Acer palmatum seedling rootstock (unpatented).
The following are the most outstanding and distinguishing characteristics of this new variety when grown under normal horticultural practices in Boring, Oreg.
This new Acer tree is illustrated by the accompanying photographs which show the plant's overall plant habit including form, trunk, and foliage. The photographs were taken outdoors in Boring, Oreg. with dates indicated. The colors shown are as true as can be reasonably obtained by conventional photographic procedures.
The following detailed descriptions are for the distinctive characteristics of ‘INAG-E61’. The data which define these characteristics were collected outdoors in Boring, Oreg. in August 2022 (unless noted) on 6-year-old and 15-year-old trees in Boring, Oreg. Color references are to The R.H.S. Colour Chart of The Royal Horticultural Society of London (R.H.S.) 2001, except where general terms of ordinary dictionary significance are used.
Table 1 shows a comparison of the differences between ‘INAG-E61’ and the commercial Maple tree ‘Bloodgood’ (unpatented).
Table 2 shows a comparison of differences between ‘INAG-E61’ and the parental lines and Table 3 shows comparison between a typical Acer pseudosieboldianum and Acer palmatum.
Acer pseudo-
sieboldianum
Acer palmatum
