45ARNOLDIAA continuation of theBULLETIN OF POPULAR INFORMATIONof the Arnold Arboretum, Harvard UniversityVOLUME 8 DECEMBER 3, 1948 Nubtsras 9-12 2NEW OR RARE ORNAMENTAL PLANTS RECENTLY DISTRIBUTEDTO COMMERCIAL NURSERYMEN BY THE ARNOLD ARBORETUMONE of the functions of the Arnold Arboretum always has been to distributenew or rare ornamentals of high quality to the commercial propagators andso make them available to the plant-buying public. Many gardeners in the north-ern United States may not have had the opportunity to realize that the ArnoldArboretum has been doing this since it was established in 1872. Propagatingmaterial of plants not available in the trade in the form of seeds, cuttings, scionsand budwood is frequently given commercial nurserymen who request specificitems. Eight years ago a special program for the distribution of new or rare plantswas started, and over 60 species and varieties of new or rare ornamental woodyplants have been distributed to commercial sources as a result. It is always easyto lose sight of the fact that new plants are being made available to commercialsources (especially when no extensive advertising accompanies the program !). In1941 a general program of propagation was started at the Arnold Arboretum inwhich particular new or rare ornamental woody plants were specifically grown forthe nurseryman.Our experience had shown (see ARNOLDIA, Series 4, Vol. VIII, No. 3, May1940) that seeds, buds, cuttings and scions when given to nurserymen frequently"failed" for several reasons. As a result, rare specimens in the Arboretum werebeing heavily cut in order to provide commercial growers with propagating ma-terial. Too often young plants propagated by nurserymen from such material,easily obtained, were quickly sold or forgotten, and requests were repeatedlymade to the Arnold Arboretum for more propagating material.As a result of years of experience, it was decided to actually grow plants herein the Arboretum, and to offer these to the commercial growers under the agree-ment with the Arboretum that such plants could neither be sold nor patented,but could be used for propagating purposes by the nurseryman receiving them.46These plants are only sent to those nurserymen requesting them specifically, sinceit is reasonable to expect that all commercial propagators are not interested in alltypes of woody plant materials.The plants noted in this issue of A RNOLDIA are either new or rare in Amer-ican gardens, and are certainly worthy of greater use. They have been sent toone or more commercial propagators as plants, and the recipient nurserymen arenoted in the following pages. Gardeners who are interested in obtaining any ofthe following plants should write the nurserymen receiving them. Plants sentout in 1947 and 1948 would not yet be available from the nurserymen, sincethere has not been sufficient time for them to propagate and grow adequate stockmaterial.The advertising benefits derived from taking out a "patent" on a plant arerather marked, but the Arnold Arboretum does not wish to limit the propagationof any of its introductions in this unique way. The following list of plants sentto commercial propagators and the probable sources from which they may bepurchased will serve as a finding list, we hope, for those adventurous gardenerswho may wish to acquire some of this material.Plants sent to cooperating nurserymen with notes accompanying them*=first introduced in the United States by the Arnold Arboretum.numbers refer to "List of Cooperating Nurserymen" (page 64), who have re-ceived the plant for propagating purposes.*Acer campestre compactum - small tree First introduced in 1900Distributed 1943 17, 18, 21, 22, 23Here is a very good form of the hedge maple which is perfectly hardy in thisarea. Because it requires little clipping, it may be valuable in certain low, in-formal hedges. The ultimate yearly growth is only about six to ten inches.Acer palmatum atropurpureum - small treeDistributed 1943 8, 11, 17, 18, 19, ~1, ~?~, 23, ~?5, 1IWe offered seedlings from a tree which has been growing on grounds adjacentto the Arnold Arboretum for nearly fifty years. The color of the foliage is adark red throughout the entire year, and it does not change to a greenish hue inthe late fall. All of the seedlings have the identical characteristics of the parentplant, including the same good color. The original tree is probably no betterthan many other trees of the same name, except that its hardiness and con-stant color have been demonstrated. This maple also has the advantage of be-ing parthenogenetic.Acer rubrum columnare - 50~~- In the Arnold Arboretum since 1899Distributed many times and 1943 19, 21, ~?~, 23, 25, 27The oldest specimen of this columnar maple which we have growing in the47Arnold Arboretum is about sixty feet tall with an approximate twelve-foot spreadof the branches. It is an easily-propagated, fast-growing maple which is valuedfor its columnar to narrow-pyramidal habit.Acer saccharum monumentale - 50~+ In Arnold Arboretum since 1885Distributed many times and in 1943 19, 21, 2?, 23, 25 5A slender, slower-growing form of the sugar maple which is dignified by thecommon name, "Sentry Maple." We have had many demands for this treeduring the past thirty years because of its narrow, upright habit, and are nowabout to stop sending out large amounts of propagating material.*Albizzia julibrissin rosea - small tree First introduced 1918 RDistributed many times and 1948 4, 11, 13, 18, 19, 21, 25, 27, 19, 31This variety, introduced into the United States by the Arnold Arboretum about1918, is more hardy than the species, and does well in Boston except in themost severe winters. Seedlings twelve to eighteen inches tall were availablefor trial. The hardiness of these seedlings is still questionable, but all seedcame from the original plant that has been growing here since 1918. Seedlingsshould be worthy of trial, but need further protection during the first fewwinters in the north. Seed is the best method of propagation at present, butroot cuttings are worthy of a trial.*Berberis triacanthophora - 4~ First introduced 1908Distributed many times and 194·1 2, 17, 19, 22, 23, 25, 27This is the hardiest and most useful of the evergreen barberries and the mostattractive. The narrow leaves are a clear, bright green in color, and it is oneof the few evergreen barberries which are immune or highly resistant to thewheat rust. As a result of this immunity, the Plant Quarantine Act