July 25, 1908 



HORTICULTURE 



97 



Notes from the Arnold Arboretum 



The effect- "I' tin' prolonged drought of the last weeks 

 was already noticeable at the Arboretum in many 

 shrubs particularly in the drier situations, when the 

 heavy showers about the beginning of this week inter- 

 vened just in time to save them. The drought affected 

 to some extent also the flowering of many plants, short- 

 ening the flowering time of some shrubs and hastening 

 the development of the flowers in others. This is for 

 instance the case with the Sorrel-tree, Oxydendrum ar- 

 bori urn . which usually does not begin to -bloom until the 

 end of the month; several small trees of it are now in 

 fall bloom at the foot of Hemlock Hill and are very 

 handsome objects viewed against the dark background. 

 This graceful tree, very attractive "with its large and lax 

 nodding panicles of small white flowers, is not so often 

 planted as it deserves. Besides its value as a late flower- 

 ing tree it is exceedingly beautiful in autumn, when its 

 foliage assumes a brilliant scarlet color. In the Alle- 

 ghanies, its native habitat, it grows into a slender tree 

 30 or even 40 feet high, but with us it itsually remains a 

 low shrubby tree; it is perfectly hardy here and begins 

 to bloom when it is still a small shrub. 



Rubus odoratus, though in flower since some time, 

 attracts now more attention when so few shrubs are in 

 bloom; with its large purple flowers and the handsome 

 maple-like leaves it is very attractive and well suited for 

 borders of shrubberies particularly in more shaded situ- 

 ations. As it spreads much by suckers, it should not be 

 planted near small and tender shrubs which would soon 

 be crowded out by it. 



Less showy are the American Diervillas of which 

 Diervilla sessiliflora and D. rivularis are in flower while 

 D. Lonicera (D. canadensis or trifida) is already out of 

 bloom. Diervilla riruhiris is a recently introduced 

 species yet but little known outside of botanic collec- 

 tions ; it is like the other species, a low shrub with small 

 pale yellow flowers in terminal clusters denser than those 

 of D. sessiliflora and much larger than those of D. Lon- 

 icera. Though the flowers of these shrubs are not 

 showy, they will help to add variety to the shrubbery 

 at this time of the year. 



A handsome shrub is Indigofera Gcrardiana, often 

 cultivated under the name of I. Dosua, a small shrub 

 with grayish green pinnate leaves and light purple 

 flowers in axillary racemes. It is not perfectly hard}', 

 but if killed back it springs up again from the base and 

 the young shoots will flower the same year. 



The original form of Hydrangea paniculata begins 

 now to flower ; it is not as showy as its more popular 

 variety grandiflora, which is not yet in full bloom, but 

 with its large panicles of creamy white flowers it is one 

 of the most conspicuous shrubs in bloom. 



Among the fruiting shrubs there ought to be men- 

 tioned in the first line Prunus virginiana var. leucocar- 

 pa, which is very beautiful with its drooping racemes 

 of amber-colored fruits ; it is certainly much more con- 



ous in fruit than the common Choke Cherry, P. 

 virginiana, which has dark purple or finally almost 

 black fruits. 



Also the Dogwood.- as Cornus stolonifera, C. alba and 

 ( '. Baileyi are now conspicuous by their clusters of white 

 fruits which will last for some time. 



Clematis tangutica, a recent 1\ introduced Siberian 

 species i- verj handsome with its large feathery heads 

 made up of fruits with long hairy tails; the large yellow 

 flowers appear in June. 



The Staghorn Sumac is now very showy with its 

 dense panicles of scarlet fruits, but still more handsome 

 is its variety Rhus typhina var. dissecta (R. typliina var. 

 laciniata of gardens, not of Wood) with its graceful, 

 finely cut foliage surmounted by the scarlet fruits; on 

 account of its fruits it is superior to the similar R. 

 glabra var. laciniata, which does not bear fruits and is 

 moreover tender in this section of the country. 



The Alder Buckthorn, Rhamnus Frangula, is attrac- 

 tive with its shining black fruits borne in small axillary 

 clusters along the branches; as the fruits when they be- 

 gin to ripen change from greenish white to red and 

 finally to black and are ripening in succession, the dif- 

 ferently colored fruits in the same clusters give a pleas- 

 ing variety; the lustrous foliage turns bright yellow in 

 fall. 



Gloxinias 



These beautiful summer blooming plants are too well 

 known to need any detailed description from me at this 

 time, and as for elaborate cultural practice it is also not 

 my purpose to enter into, as this has been threshed over 

 and over again with no small skill. 



My purpose is simply to endorse the never-failing 

 charms of the subject of the frontispiece of this paper t 

 which, in this particular case, is a nice specimen plant 

 of the so-called "Spotted Gloxinia." Amongst them 

 usually are to be found elegant types. Choice types 

 when they do appear should be jealously taken care of 

 and seed secured from them. In doing this practical 

 isolation from inferior kinds is absolutely necessary. 

 To perpetuate true to the original extra kinds as they 

 appear, leaf cuttings are resorted to. Considerable fas- 

 cination, on the other hand, attaches always to the spec- 

 ulative results from new seed, whether that be from the 

 ordinary sources of supply or from, our own labors in 

 this line. Gloxinias, though delicate and easily bat- 

 tered by rough handling, are among the longest keep- 

 er- as cut flowers. They are furthermore indispensable 

 to the gardener for keeping the greenhouse gay in the 

 summer and autumn months. 



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