646 



HOKTICULTURE 



May 19, 1917 



Effects of the Winter. 

 The effects of the heavy rainfall of 

 the past summer and of the hot dry 

 autumn which thoroughly ripened the 

 wood of trees and shrubs are now 

 shown in the generally good condition 

 of the Arboretum collections which 

 promise abundant crops of flowers and 

 fruit. A few flower-buds have been 

 killed, and there are occasionally 

 brown leaves on Rhododendrons and 

 other broad-leaved evergreens, but not 

 80 many as usual at this season of 

 the year. Exotic conifers, including 

 the new Firs, Spruces and Pines from 

 western China, are generally uninjured 

 but the foliage of the native White 

 Cedar (Chamaecyparis thyoides) is 

 badly disfigured. For some reason not 

 easy to explain this tree has never 

 taken kindly to the Arboretum condi- 

 tions, and suffers here more or less 

 every winter. It is a late spring in 

 eastern Massachusetts. 



Winter-flowering Witch Hazels. 



The flowers of these interesting 

 plants have never been more beautiful 

 and abundant than this year, although 

 they appeared much later than usual. 

 The flowers of Hamamelis vernalis, 

 the species from southern Missouri, 

 usually open late in December and in 

 January, and those of the Japanese 

 and Chinese species are usually fully 

 open in January and February; but 

 with the exception of a few precocious 

 flowers on a branch of one of the 

 plants of H. vernalis which opened late 

 in December, none of these plants were 

 in flower this year until the middle of 

 March. In the size of the flowers and 

 in the length and brilliancy of the 

 bright-yellow petals Hamamelis mollis, 

 a native of western China, is the hand- 

 somest of all the Witch Hazels. The 

 pale green foliage of this shapely 

 shrub is also attractive. It is very 

 hardy and grows rapidly, and might 

 well find a place in any garden or city 

 plot in public view during the winter 

 months. This Witch Hazel is one of 

 the most valuable and interesting 

 shrubs brought in recent years to the 

 United States. 



Prunus Davldlana. 



This is the earliest of the Plum, 

 Cherry, Peach and Apricot groups to 

 flower this year. It is one of the wild 

 Peaches of northern China, and is a 

 small tree with lustrous red-brown 

 hark, slender erect branches which 

 form a narrow head, small flowers, nar- 



row pointed leaves and small fruit of 

 no edible value. The flowers are 

 usually of the color of those of the 

 common Peach-tree, and there is a 

 form with pure white flowers. The 

 two forms have been covered with flow- 

 ers during the past week in the Peach 

 and Apricot Group. As a flowering 

 tree in this climate this Peach has 

 little to recommend it for the flower- 

 buds or the flowers are killed almost 

 every year by late frosts, but just now 

 pomologists in this country are in- 

 terested in it as a possible stock on 

 which to work the common Peach-tree, 

 as it is hardy north of the region 

 where the Peach thrives. 



Early Rhododendrons. 



Several plants of the Siberian and 

 north China Rhododendron dahuricum 

 have been in bloom during the past 

 week. This shrub has been in Euro- 

 pean gardens for more than a century 

 but is still little known in the United 

 States. It has small dark green leaves 

 which in this climate remain on the 

 branches until late in the winter, and 

 small bright rose-colored flowers. These 

 are often destroyed by spring frosts, 

 and this plant has never been so beau- 

 tiful before in the Arboretum as it is 

 this spring. There is a variety sem- 

 pervirens with more persistent leaves 

 and darker-colored flowers. This va- 

 riety is not blooming this year. 

 Usually Rhododendron mucronulatum 

 is the earliest of the Rhododendrons to 

 bloom in the Arboretum but this year 

 it is a week later than R. dahuricum, 

 and is only now opening its paler rose- 

 colored flowers. This is a tall, perfect- 

 ly hardy, deciduous-leaved shrub which 

 has flowered freely every spring in the 

 Arboretum for the last twenty years 

 and is chiefly valuable for the earli- 

 ness of the flowers which appear on 

 the leafless branches and are rarely in- 

 jured by spring frosts. In the Arbore- 

 tum the leaves turn bright yellow be- 

 fore falling late in the autumn. 



Early Magnolias. 



The flower-buds of the Japanese Mag- 

 nolia stellata have been nearly all 

 killed in the Arboretum. This should 

 not, however, discredit this beautiful 

 shrub, for the plants here are in low 

 ground and in a particularly trying 

 position, and in other Massachusetts 

 gardens plants of this Magnolia have 

 not been injured and are now in full 

 bloom. The flower-buds of the other 

 early-flowering Japanese species, Mag- 



nolia kobus and its variety borealis, 

 have not been injured and are now just 

 opening. As flowering plants they are 

 the least desirable here of the Mag- 

 nolias which bloom before the leaves 

 appear, for the flowers are not large 

 and only exceptionally are produced 

 in large numbers. 



Daphne Mezereum. 

 A plant of the white-flowered form 

 of this small European shrub has been 

 in bloom for the last two weeks. The 

 purple and the white-flowered forms 

 are useful garden plants because they 

 are almost the first shrubs to open 

 their flowers in this climate and be- 

 cause the flowers are not injured by 

 spring frosts. This Daphne is interest- 

 ing to us in this country because it is 

 one of the few shrubs native of Europe 

 which have become widely naturalized 

 in some parts of North America, as in 

 eastern Massachusetts and on the 

 Canadian side of the Niagara River 

 above the Falls. 



The Cornelian Cherry. 

 Which is a Dogwood (Cornus mas), 

 is one of the earliest trees or tree-like 

 shrubs with conspicuous flowers to 

 bloom in eastern Massachusetts. The 

 flowers are light yellow and are home 

 in clusters in the axils of the unfold- 

 ing leaves and, although individually 

 small, are produced in such profusion 

 that the branches are covered with 

 them. The flowers are followed by 

 bright red, lustrous, oblong fruits the 

 size of small olives. The flower-buds 

 and the flowers of this tree are not in- 

 jured by cold. The habit of the plant 

 is good; the foliage is dark green and 

 abundant, and the fruit, although 

 somewhat hidden by the leaves, is 

 handsome. The Cornelian Cherry, 

 which is a native of Europe and west- 

 ern Siberia, has been an inhabitant of 

 gardens for more than three hundred 

 years. In the United States it was 

 probably more often planted in the 

 first half of the last century than it 

 is at present, although there are not 

 many early-flowering trees hardy in 

 this climate which are better worth a 

 place in the garden. The largest speci- 

 men we know in eastern Massachusetts 

 is in the Public Garden of Boston. 



Early-flowering Native Shrubs. 

 Two yellow-flowered native shrubs 

 are in flower and are well worth the 

 attention of the makers of American 

 gardens by whom they have been 

 generally neglected. These are the 

 Leatherwood, Dirca palustris, and the 

 aromatic Spice Bush, Benzoin aesti- 

 vale. Their leafless branches are now 

 covered with small yellow flowers, and 

 those of the Spice Bush will be fol- 

 lowed in the autumn by scarlet Ins- 



