August 13, 1910 



HORTICULTURE 



199 



Notes From the Arnold Arboretum 



A genus of summer-flowering shrubs which seems not 

 so well known as it ought to be, is Hypericum, with sev- 

 eral native shrubby species well worth cultivating. They 

 are generally bushes of rather regular round shape from 

 three to six feet high and during July and August they 

 are covered with bright yellow flowers. One of the best 

 is Hypericum prolificum which forms when standing 

 alone a round bush from three to four feet high with 

 oblong dark green leaves one to three inches long and 

 bright yellow flowers about tliree-quarters of an inch 

 wide bome in many-tiowered clusters at the end of the 

 branches. Similar is Hypericum densiflorum with more 

 numerous, but smaller flowers and narrower leaves; it 

 sometimes grows to the height of six feet. Very showy 

 is H. aureum with golden yellow flowers often two inches 

 in diameter, but not as numerous as in the preceding 

 species, and with broader glaucous foliage. It reaches 

 a height of four feet and forms a rather regular round 

 busli. Hypericum Ealmianum is similar to the first 

 named species, but somewhat lower and of less regular 

 and more straggling habit; the leaves are narrowly ob- 

 long and dark bluish green and the flowers slightly 

 smaller and not as numerous. This species is the hardi- 

 est of the shrubby kinds, being a native of the great 

 lake region, while all the others come from the south. 

 Closely allied to H. Ealmianum is H. lobocarpum from 

 Tennessee, which also has proved hardy at the Arbor- 

 etum; both these species are easily distinguished 

 by their five-celled fruit and their five styles, while 

 tiie others have three styles and a one or three-celled 

 fruit. A lower plant rarely exceeding two feet is H. 

 galioides with very narrow linear leaves and small flow- 

 ers less than half an inch in diameter forming leafy 

 spikes at the end of the branches. It is perhaps less 

 showy than the other species, but of very distinct ap- 

 pearance with its almost needle-like foliage and low 

 dense habit ; it is a good plant for borders of shrubber- 

 ies. Hypericum nudiflorum has proved here a poor 

 grower and is apparently not quite hardy, but may do 

 better farther south. It forms a shrub from one to 

 three feet high with oblong leaves and bright yellow 

 flowers in flat, stalked clusters four to five inches broad 

 at the end of the branches. Within the last few years 

 two or three hybrid forms have originated at the Arbor- 

 etum between Hypericum Ealmianum, H. prolificum 

 and H. galioides. These seem to be more vigorous and 

 more floriferous than the parent species, as it often is 

 the case with hybrids and therefore will probably prove 

 welcome additions to our summer-flowering shrubs. 

 They need, however, further investigation and study be- 

 fore anvthing definite can be said about their horticul- 

 tural properties and their botanical state. The prop- 

 agation will be easy, as the Hypericums grow readi- 

 ly from greenwood cuttings in summer. The different 

 species can also be grown from seed which germinate 

 readily and the seedlings begin usually to bloom the 

 second year. 



Mention may be made here of a species from south- 

 eastern Europe and western Asia, which, though not 

 perfectly hardy at the Arboretum, ought to be recom- 

 mended as a fine ground-cover in suitable localities. 

 This is H. calycinum.. Rose of Sharon ; it scarcely exceeds 

 one foot in height, but by means of its creeping stems 

 and suckers it covers rapidly large stretches of ground, 

 particularly in light and sandy soil, with a dense carpet 

 of its handsome evergreen foliage. The golden yellow 

 flowers are very showy and measure about three inches 

 in diameter. 



Another handsome shrub witli vellow flowers now in 



full bloom is Colutea cilicica (C. longialata) . It is sim- 

 ilar to the better known C. arborescens, but does not 

 seem to grow quite as high and the foliage has a very 

 distinct light bluish color, like that of C. orientalis 

 which, however, is tender here, while C. cilicica has 

 proved perfectly hardy at the Arboretum. It is par- 

 ticularly valuable on account of its late flowering time. 

 After C. arborescens and other species are out of bloom 

 it is covered with its numerous drooping clusters of 

 light yellow flowers. The species had been introduced 

 into the trade in Europe under the erroneous name of 

 C. melanocalyx, but is as yet almost unknown in this 

 country. 



Seasonable Notes on Culture of 

 Florists Stock 



ABALIAS 



When the seed of Aralia Sieboldi arrives, which is 

 about this time, it should be so\vn as soon as possible, 

 as it loses its vitality in a very short time if allowed to 

 become dry. Sow in a mixture of loam, leaf mold and 

 sand and keep moist and shaded from the sun. Wien 

 the seedlings are large enough to handle pot into 3 or 

 S^'o-inch. Shift when large enough as they soon suffer 

 from being pot-bound. Keep the atmosphere moist, 

 and jjlenty of water at the roots. If you have any 

 young stock outside house them before danger of frost. 

 The old plants can stay out longer as they will stand 

 considerable frost. Watch out for scale. 



COLD STORAGE LILIES FOE CHEISTMAS 



By starting cold storage longiflorums from. August 

 15 to 20th you will give them more time for root action. 

 Start in as cool a place as you have. Don't expose 

 them to a very bright sun until the approach of their 

 flowering time. The most advanced of these lilies can 

 be had in bloom for Thanksgiving and from that date 

 on. Have your soil moderately moist and the bulbs will 

 not need any water for weeks. Longiflorums want very 

 little water until they have made good roots, but when 

 I hey «tart and have filled their pots with roots they will 

 require an abundance of it. The first consideration is, 

 of course, to secure good bulbs. There are several firms 

 that make a specialty of handling these cold storage 

 lilies and the most reliable will always be found in the 

 advertising columns of Hokticultdee. 



COMPOST FOE WINTEE 



To prepare a compost for use in the greenhouse dur- 

 ing the winter is one of the most important jobs to be 

 seen to at this time. The compost that was got to- 

 gethcr some time ago should now be turned over and 

 well broken up, so as to be in readiness when wanted. 

 A compost consisting of two-thirds loamy sod to one- 

 third of well decomposed cow manure will answer ad- 

 mirably for the average florist who handles a variety of 

 crops. Now is the time to get sod for next year's bench 

 crops. Some land that has been in pasture for a num- 

 ber of years will make an ideal compost. The more 

 fibrous it is, all the better. It should be stacked in 

 square piles and about six feet high. To every two or 

 three loads of sod, add a load of well-rotted barn-yard 

 manure, cow manure being preferable. 



EOMAN HYACINTHS 



This class of bulbs are due to arrive this month and 

 can be planted as soon as received. Use boxes of a uni- 

 form size, about three inches deep and of dimensions 

 easy to handle. Any ordinary good soil that has been 



