ORNAMENTAL AND SHADE TREES 



683 



your conclusions, though, as a nurseryman, I might think that 

 government competition with private business is not altogether 

 fair. Surely there should be uniformity in street planting ; my 

 own street, with a mixture of sugar and Norway maples, elms 

 and even Carolina poplars, is an example of the tree-seller's mis- 

 guided efforts and the buyer's ignorance, while the gymnocladus 

 in front of my own place, planted by a former owner, cause me 

 daily to regret what I might have had. The bad effects of indi- 

 vidual plantings have called for city action forbidding the plant- 

 ing of certain varieties. 



" Recently, I read in one of the florist papers a correspond- 

 ent's report from St. Louis that the Board of Aldermen of that 

 city had passed an ordinance authorizing the city forester to 

 designate streets requiring shade trees : to buy them and have 

 them planted ; the cost to be assessed as taxes against the owners 

 of the abutting property. If true, that is rather advanced legis- 

 lation, but very sensible, too. It is putting the matter of health 

 and comfort from street shade trees in the same catalogue with 

 lighting and paving and side- walks ; and why not? 



" Do you know if this is correct as reported, and do you 

 know of any other cities doing the same thing?" 



A. In making the suggestions to which he refers we were 

 naturally speaking of conditions as they practically exist in a great 

 many cities all over the country, and were recommending that 

 cities specialize in trees such as oriental planes and maples, which 

 they constantly need for replenishing their streets, and were not 

 recommending that cities go into the nursery business with the 

 idea of raising ornamental stock which requires a great deal 

 of special care. We think that our cities ought to buy most of 

 that stock, but we can see no harm in their raising such trees as 

 we mention. In fact, we do not see how you can stop them, because 

 they are already doing it to a great extent. One thing we can 

 help a great deal is the close cooperation between city foresters 

 and nursery men. As to the shade tree ordinance which you 

 speak of, there is nothing new in that, and such cities as Newark, 

 and East Orange, New Jersey, and 50 others throughout the 

 country have done that years ago. We shall be glad, however, to 

 have expressions of opinion on these points from other in- 

 terested readers. — The Editor. 



Q. I lost two large trees that had been bearing large, fine 

 dark blue plums. I do not know the name of the variety. A 

 dark, hard and warty growth appeared on the branches. It spread 

 so far and fast, and filled and withered the branches and leaves 

 to such an extent that I had to cut them down. I burnt them up 

 for fear of the infection spreading. I find I have been a bit 

 late in this, for on examination I see it exists to some extent on 

 some of my other plum trees of Japanese variety. I am told the 

 disease is called the black knot, but I should like to have full in- 

 formation as to what it is, how to check it where now existing, 

 how to prevent its spreading, if it is necessary to disinfect and 

 treat the soil, and I desire particularly to know if the pruning, if 

 advisable, is to be done at once or when the trees have shed 

 their leaves. At the latter time it, of course, is more apparent and 

 a better and cleaner job can be done. I am sending specimens. 

 E. K., Little Boar's Head, New Hampshire. 



A. The disease is the regular black knot of the plum, as you 

 thought. It is caused by the fungus Plo-wrightia morbosa. New 

 infections take place in the spring and early summer, and the 

 knots continue to grow throughout the growing period of the 

 tree. By examination with a hand-lens, you will note that the 

 surface of these knots is covered with innumerable round, black- 

 ish bodies, the fruiting bodies of the fungus. These, however, 

 do not mature their spores until March of the following season. 

 The work of eradication, therefore, can proceed at any time 

 when convenient between now and next March, preferably after 

 the leaves are off. On the larger limbs and branches make the 

 cuts at least four to six inches below the knots, as the mycelium 

 of the fungus extends a short distance beyond the swellings. It 

 is a good plan to burn up the knots and then in bad cases to 

 spray the trees with Bordeaux mixture before the buds swell. 



Q. I am having at the moment great trouble with our pine 

 trees. They have been perfectly healthy but are turning yellow, 

 several have died already— all within the last month— four have 

 gone entirely and others look " sick." There are no wild currant 

 or gooseberry bushes near the trees. They are quite large trees. 

 As the chestnuts died, we replaced them with pines, spruce, larch 

 and maples, all of which trees do well here. We have many fine 

 old hemlocks. 



A. With further reference to your pine trees, I am able to 

 tell you the opinion the laboratory has expressed relative to the 

 condition. Judging from the specimens, it seems that this is a 

 physiological trouble, probably caused by e.xtreme weather condi- 

 tions last winter, which have affected a small part of the sap- 

 wood through which the water is conducted from the roots up- 

 wards to the leaves. The hot, relatively dry weather which we 

 have had recently has resulted in a greatly increased demand by 

 the leaves for water. Until this time, the sap-wood, only a part 

 of which is affected, has been able to supply sufficient water, 

 but this sudden, much increased demand has been greater than 

 the diseased wood could supply. The result is a partial short- 

 age among the branches, with the scorching appearing very sud- 

 denly. This is the way I have figured out the whole trouble from 

 the appearance of sap-wood and all the other circumstances. It 

 is a matter which is, at least with our present facilities, not pos- 

 sible for us to definitely prove by experiment. We believe, how- 

 ever, this is the truth of the matter. Records kept for several 

 years upon diseased trees showed that most of them recovered 

 the second year, and that only a relatively few died from the 

 effects. So far as we can judge, there is no treatment which is 

 likely to aid this trouble. 



Q. Two of my Norway maples have died all of a sudden this 

 fall. All the neighboring trees of the same variety are in good 

 condition. I do not know how to account for it except that I 

 placed some cotton dipped in kerosene around the trunk last 

 spring and repeated it several times. My intention was to ward 

 off caterpillars. 



H. M., Hempstead, Long Island. 



A. A continuous application of kerosene to the bark of 

 trees is likely to do serious injury. 



Q. What is the best way to seed a steep bank and what 

 grass shall I use for my lawn? 



A. L., Neiv York City, Nezv York. 



A. If the bank is very steep, the safest way is to use sod 

 instead of seed, or else it will wash down before the seed is 

 established. For the lawn the best seed would be a combination 

 of equal parts of fescue, Kentucky blue and creeping bent. You 

 might also introduce a very small quantity of small-leaf white 

 clover. 



Q. My hickory trees have turned brown within the past 

 few weeks and many of them look entirely dead. Can you ac- 

 count for it? Will they come back again next year? 



W. S., U'aterbury, Connecticut. 



A. Your hickories have evidently been killed this year by the 

 hickory bark beetle. You should have that determined definitely, 

 and, if so, the infested trees should be cut down and burnt 

 before May. They will never come back to life. 



Q. I want to set out some nice hybrid rhododendrons this 

 fall. What are the best varieties ? 



R. H, L., Orange, New Jersey. 



A. Tills is not the season for planting rhododendrons. 

 Spring is the best time. Tlie following varieties are good : Kettle 

 drum, .Abraham Lincoln. H. W. Sargent, General Grant, Ever- 

 estrianum, Charles Dickens, Lady Armstrong, Parsons grandi- 

 flora, etc. 



