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HORTICULTURE 



May 25, 1907 



useful wei-e adopted into ciiltivation. When botanical 

 societies, imiscums, and gardens were established, many 

 exotic plants were grown and brought into flower or 

 fruit, and their excellence became known to horticul- 

 turists. The old volumes of the Botanical Magazine, 

 the Botanical Register, and other ^uch publications, 

 with their fine old colored plates illustrate how this 

 was, and how scientific botany, under the stimulus 

 which came so largely first of all from Linnaeus, brought 

 to the light of public knowledge many most beautiful 

 j)lants. 



Of course it goes almost without saying that every 

 time one uses the botanical name of a plant, he incurs a 

 debt to Linnseus, who devised the method of designat- 

 ing all species by binominal terms. Linnaeus saw that 

 in place of the descriptive phrases of irregular length 

 by which plants were known, two words were enough 

 for the name of each plant, one word for the genus, 

 one for the species.; as is Spinxia japonica, Ulmus Amer- 

 icana, Cattleya labiata, etc. The whole world follows 

 him in this binominal system of plant-names. More 

 directly practical botany was aided by the travels and 

 the works of the pupils of Linnaeus, some of whom are 

 mentioned above, wliose names are commemorated in 

 familiar plant-names, as Kalmia, Thunbergia, etc. But 

 the chief debt to Linnaeus of everyone who deals with 

 plants must always be for the great impulse which his 

 clear arrangement of the vegetable kingdom gave to the 

 study of the plant world. 



tJd4^ 



Hydrangea arborescens grandiflora 

 alba 



Plants of this handsome hydrangea are blooming in 

 the little greenhouse at the Arnold Arboretum, and 

 attract much admiration from all visitors. Mr. Daw- 

 son says that these plants were placed in the pit in 

 December and were started in the house in February up 

 to which time they were only dry sticks, this proving 

 that it is unexcelled as an Easter forcing jjlant with 

 every qualification for great popularity. The flower 

 heads are very large, pure white and entirely jacking 

 the coarseness of Otaksa or Thomas Hogg. The foliage 

 is light green, smooth, heart-shaped and very effective. 

 Mr. Dawson pronounces it one of the very best intro- 

 ductions, either foreign or American. Prof. C. S. Sar- 

 gent calls attention to the fact that Asa Grey described 

 this sterile form of Hydrangea arborescens as having 

 been found in the mountains of Pennsylvania sixty 

 years ago and it is vemarkable that it should have re- 

 mained in obscurity for so many years. E. G. Hill & 

 Co. have the credit of first bringing it into public 

 notice. 



Plants in the Rock Garden 



The article in a recent issue of HoirncuLTUUii on 

 "Alpine flowers in a cold greenhouse" was of great inter- 

 est to me. "When I was at Kew there was no house for 

 alpjnes, and, during my visits since then I was not fortu- 

 nate enough to be there to see the house at its best in 

 April and May. It seems to me that the plants and 

 interior of the house would look much better if a small 

 rockery was built in the house. The plants would look 

 much moi'e iiStural and probably grow much better, too, 

 if gi'own in a rock. There is a charming rockery out- 

 of-doors at Kew, but the plants do not seem as happy 

 or as thrifty as the alpine plants in the rockery at the 

 Edinburgh Botanic Garden. Probably the Scotch mist 

 which wets an Englishm.an to the skin agrees well with 

 the mountain jewels or alpine plants. 



The past month, April, will be long remembered for 

 its unseasonable weather. Many plants that ought to 

 have blossoiiifid during the month were retarded as 

 safely as if they were kept in cold storage. The princi- 

 pal plants that blossomed during April were crocuses, 

 snowdrops .grape hyacinths, glory of the snow, hepati- 

 cas and a fcv.' narcissi. 



There is probably no part of the garden so interest- 

 ing in May as the rock garden. The plants have win- 

 ter eu well. The deep coating of snow which covered 

 them mostly all the winter kept them safely and from 

 alternate freezing and thawing. Plants are especially 

 thrifty and promise to give an exceptionally liberal 

 supply of blossoms. 



TIIK UOCK CIi£?,SES 



Large masses of the white rock cress (Arabis albida) 

 is most pleasing at this early season. It is an old-fash- 

 ioned plant but it will be a long time before we are 

 tired of its company. Its white, fragrant flowers are 

 most pleasing when planted in large masses and will 

 do well in almost any soil or situation. Another species . 

 that is less known btit a gem of rockery plants is Arabis 

 proeurrens. This plant has a mat of white flowers 

 which stand six or eight inches in height. It is valu- 

 able as a foliage plant when destitute of flowers. It 

 makes a thick mat which covers the ground completely 

 with its bright green leaves which are bright and green 

 tliroughout the whole season. 



The purple rock cress that does best with us is Au- 

 brietia dcltoidea. In elevated positions where water 

 does not lodge, about it in winter it will grow well and 

 flower profusely. Phlox subulata and its varieties are 

 always at home and happiest in the highest and driest 

 parts of the rock garden and are so showy that they 

 draw attention from a distance. Euphorbia Myrsinites 

 although not a showy plant when in bloom is valuable 

 for hangin.o- gracefully over the rocks and its light 

 .slaucoup-gi-cou foliage and stems arc quite attractive. 

 It sows itself freely in our garden. 



^fany of the species of the dog's tooth violets have 

 lieauti fully marked foliage and would be well worth 

 .iXrnwing for this attribute alone. At this time they are 

 llnv.ri-iiin' witli tbi' greatest freedom and the European 



