text: the following is a detailed description of the invention based on plants grown at the research station of viticulture and horticulture in geisenheim , hessen , germany . color descriptions and other terminology are used herein in accordance with ordinary dictionary significance or as commonly used by those of ordinary skill in the relevant art , unless otherwise noted with reference to the royal horticultural society colour chart ( r . h . s .). it should be noted that color will vary with time of year , lighting and growing conditions . for example , leaves tend to be brighter green if grown in soil with a high nitrogen content and more yellow if grown in soil with lower nitrogen content . all ` rhenus 2 ` trees , insofar as i have been able to observe them , have been identical in all the characteristics described below . propagation : holds to distinguishing characteristics through succeeding propagation by rooted cuttings . trunk .-- size : fig2 provides a view of typical two - year - old nongrafted specimens . fig3 provides a view of five - year - old ` red haven ` trees grown on ` rhenus 2 ` rootstock ( right ) and , for comparison purposes , on ` nemaguard ` rootstock ( left ). the trunk caliper on two year old tree growing in dundee , oreg ., was one - eighth inch measured about one inch above the ground . surface texture : smooth . bark color : bright gray - brown ( like r . h . s . 178c on one year old trunk and r . h . s . 177a on two year old trunk , growing in dundee , oreg .). branches .-- surface texture : smooth . bark color : red - brown . new growth color : bright green . mature growth color : red - brown . like r . h . s . 175a on mature one year branches . mature one year branches are those that have matured over the summer of a single growing season . internode length : 15 - 20 mm . lenticels : yellow - white , pointed - rounded ( like r . h . s . 163c ). bud : color observed in spring in dundee , oreg ., was brown , like r . h . s . 177b . leaves .--( see fig1 ). size : generally small . length averages 70 - 80 mm , including the petiole . width averages 20 - 25 mm . surface texture : normal for the species . form : linear elongated . color : upper surface is bright to dark green ( like r . h . s . 137d when observed in dundee , oreg . in the spring ). lower surface is bright gray - green ( like r . h . s . 139c when observed in dundee , oreg . in the spring ). mid - vein : size : average . color : yellow - green . petiole : length normal for species , 10 - 15 mm . thickness 0 . 2 - 0 . 3 mm . color is yellow - green to green ( like r . h . s . 137d when observed in dundee , oreg . in the spring ). no leaf glands observed . flowers .-- size : small , about 5 mm in diameter . color : white ( like r . h . s . 155c ). number : 2 - 4 per bud . fragrance : very weak . sexual characteristics : flower is complete , fertile , but self - unfruitful . fruit .-- no fruit borne by ` rhenus 2 ` trees in six years of observation . compatibility .-- very good . no incompatibility observed with any peach or nectarine variety . no incompatibility with apricots after four years &# 39 ; testing . compatibility expected with most other prunus species , although incompatible with at least some varieties of european plums . vigor .-- dwarfing . prunus tree scions grafted to ` rhenus 2 ` rootstock are approximately 70 - 80 % as vigorous as when grafted to ` nemaguard ` rootstock . ` rhenus 2 ` is useful , for example , as a dwarfing rootsock with peaches , nectarines , and apricots ( p . armeniaca ), as well as with other prunus species such as plums ( e . g ., p . domestica , p . salicina ). although incompatibility has been observed with some varieties of european plums , ` rhenus 2 ` is compatible with all varieties of peaches , nectarines , and apricots that have been tested and no graft line problems have been observed . for example , the trunk circumference of a ` red haven ` scion grafted to ` rhenus 2 ` rootstock is reduced by about 34 percent compared to a ` red haven ` scion grafted to ` nemaguard ` rootstock ( 155 mm and 235 mm , respectively ) ( table 1 ). ` nemaguard ` is an unpatented rootstock which is commercially available . also , the yield efficiency of ` red haven ` peach scions on ` rhenus 2 ` rootstock is approximately 52 percent higher than ` red haven ` peach scions on ` nemaguard ` rootstock ( table 1 ). scions grafted to ` rhenus 2 ` also display early yield or precocity ( i . e ., a cumulative marketable yield of fruit of a variety grafted to ` rhenus 2 ` rootstock that is significantly higher five or six years after planting as compared with the same scion variety grafted to a reference rootstock ). in general , the yield of a prunus scion grafted to ` rhenus 2 ` rootstock is about one year earlier than when grafted to ` nemaguard ` rootstock . moreover , ` rhenus 2 ` displays high frost hardiness . in a cold treatment trial , ` rhenus 2 ` exhibited no observable damage when subjected to a temperature of - 15 ° c . for fifteen days , while other peach rootstock selections died or were severely injured . the following tables provide data regarding the growth of peach varieties grafted as scions to ` rhenus 2 ` and comparisons of the red haven peach variety grafted to both ` rhenus 2 ` and ` nemaguard ` rootstock . no significant fruit size differences or graft line problems were observed . measurements are made 10 - 20 cm above the bud union on grafted trees . table 1______________________________________trunk circumference and tree head volume ofpeach varieties grafted to ` rhenus 2 ` or ` nemaguard ` rootstock five years after planting tree circum - tree headvariety rootstock ference ( mm ) volume ( m . sup . 3 ) ______________________________________sunglo rhenus 2 176 1 . 2sunking rhenus 2 173 1 . 2fairhaven rhenus 2 143 1 . 0hale berta rhenus 2 157 1 . 2giantred haven rhenus 2 155 1 . 2red haven nemaguard 235 5 . 3______________________________________ table 2______________________________________yield efficiency / productivity and fruit weightof red haven grafted to ` rhenus 2 ` and ` nemaguard ` rootstock yield fruitvariety rootstock efficiency * weight ( g )** ______________________________________red haven rhenus 2 79 96red haven nemaguard 52 106______________________________________ * total yield 1986 - 1991 ( kg ) divided by trunk circumference ( mm ). ** average of four years .