January 4, 190S 



HORTICULTURE 



A New Disease of the Peony 



To the iuiuiteiu- liorticiilturist, that is, oue who grows 

 plants for jilcasiire rather tlian for money, the peony 

 lias been, and probably always will be, a great favorite. 

 The dark green foliage throughout a long growing sea- 

 son, the largo flowers, the endless number of varieties, 

 its comparative freedom from disease and the small 

 number of insects which trouble it, have all contributed 

 more or less to its deserved popularity. Hence it is 

 that peony -lovers in and aljout Cambridge, Mass., have 

 viewed with dismay the destruction of many of their 

 favorite plants the past season by a new disease. 



Among the first symptoms of the disease are wilting 

 of the leaves and loss of green color in the stalks. On 

 digging away the earth the roots are found more or 

 less decayed. In a majority of cases^ though not always, 

 the disease is fatal. Specimens of the diseased plants 

 have been sent to the experiment stations, but so far no 

 satisfactory conclusions have been reached. Probably 

 some bacterium or fungus is the cause of all the trouble, 

 but tlie ]iarticular species has not yet been determined, 

 nor is it known whetlier infection taKCs place above or 

 lielow the ground. 



If it should be proved that the disease is spread by 

 sjiores that are blown about by the wind and germinate 

 ou reaching the leaf, the remedy mav be simple, for 

 s))raying with Bordeaux mixture or other fungicide 

 would undoubtedly be sufficient to protect the plants 

 from future attacks. But it appears, more likely that 

 infection takes ]ylace in the soil and that the root is the 

 first part of the plant to undergo destruction. In this 

 case to insure the immunity of the plant will not be so 

 easy. 



If the cause of the trouble is a species which is 

 usually parasitic and lives in the soil, the grower of 

 peonies has some reason for being alarmed as tlie con- 

 trol of such species is difficult. They are seldom kept 

 from doing harm except by rotation of crops as the 

 ease of onion smut, club-foot of cabbage and potato 

 scab. Yet it may be that the peonv disease is only a 

 saprophytic form (that ordinarily lives on decaying 

 matter only) which has become under favorable con- 

 ditions temporarily a parasite. If such is the ease an 

 amelioration of the soil by applications of lime, sand, 

 or other material may be sufficient to prevent further 

 ravages. 



Prof. M. L. Fernald of the Botanic Garden, Cam- 

 bridge, who has made ait extended study of the geo- 

 graphical distribution of plants as affected by their 

 physical environment, says that many members of the 

 l\anunculace£e (Buttercup Fainily) to which the peony 

 belongs, delight in a limestone soil. So far as known 

 Ibe peony disease luis a]ipo;ired only iri clayey soils 



where there is, presumably, only a small amount of 

 lime. And it may be that the peony having been trans- 

 ported from its natural environment has become so 

 weakened that the saprophytic organisms have been able 

 to attack the hist plant before natural dpcay of the 

 roots has begun. , 



In the meantime, while we await the decisions of the 

 plant pathologists who are studying the disease, we 

 advise the peony-gi'ower who wishes to save his plants 

 to begin spraying all parts of the plant above the soil 

 as soon as the leaves appear in the spring. This will 

 l)revent any infection by spores blown about by the 

 wind. To retard any further spread of disease in the 

 soil, lime should be broadcasted at the rate of fifty to 

 seventy-five bushels per acre and spaded in thoroughly 

 as soon as the ground can be worked. These preven- 

 tives may not prove to be an unqualified success, but 

 they are the best known'at present. 



E. W. Morse. 



Celastrus orbiculatus Thun, 



Even now this Asiatic cousin of our own Bitter 

 Sweet or Eoxbury Wax Work is showy with its wealth of 

 crimson seeds. Although introduced into this country 

 more than thirty years ago it is by no means as com- 

 monly planted as it deserves. A twining shrub, native 

 to China and Japan, it attains a height of ten to fifteen 

 feet and in habit closely resembles the Wax Work 

 though it is a more vigorous plant and a more rapid 

 grower. The leaves are usually two to three inches 

 long, dark yellow-green on the upper surface and turn 

 to yellow before falling in the autumn. The flowers 

 are small, yellow-green, borne in axillary clusters and 

 are of little ornamental value. The fruit is very abun- 

 dant and ripens in early autumn. It is globose and 

 about one-cpiarter inch in diameter. The pod is a clear 

 yellow and the aril of the seed crimson. The fruit is 

 smaller than that of the Eoxbury Wax Work and is less 

 showy until the leaves have fallen because the fruit 

 stalks do not lift it above the leaves. Then the aril is 

 lighter in color and somewhat less striking than that of 

 the Wax Work. However, the greater abundance of 

 fruit more than compensates for these deficiencies. As 

 to persistence, the pod usually remains until late fall 

 or early winter, while the seed with its crimson aril not 

 infrequently remains until late winter. It is not par- 

 ticular as to soil or situation and it grows in the shade 

 as well as in the sun. It is especially good for covering 

 rocks and for twining over walls and fences. Then it 

 is well adapted to house decoration, a purpose for which 

 it is made to serve by the Japanese. 



Celastrus orbiculatus is figured and described in "Garden 

 and Forest", vol. Ill, pp. 550-551. 



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