Readers' Problems:—Some Queries Answered

New Zealand Herald, Volume LXXV, Issue 23121, 20 August 1938, Page 10 (Supplement)

Readers' Problems: —Some Queries Answered

Thrlps on Rhodondendron. —(1) I am en closing cutting of rhododendron. Can you toll me what is wrong with it and is there a spr.iy that would clean it up? (12) Also could you tell me the name of the enclosed cutting? Grown from seed about three years ago and has not flowered yet. Height, about five feet. —E.B., Te Hana. Rhododendron is badly affected by thrips. Spray occasionally with white oil emulsion at 2 per cent strength. Alternatively use lime sulphur at a strength of 1 in SO during the evenings in summer. Do not spray with this in the heat of the day. Burn all fallen leaves. (!2) Native shrub, Olearia virgata. Coal Ashes in Garden. —In past years when burning wood I found tlio nshes beneficial to flowers and vegetables. This year wo are using a lot of carboncttcs also. Will the ashes now be useful in the garden, or the reverse? — Mrs. M., Onehunga. While wood ashes are beneficial to most soils for the potash they contain, their value is of course lessened by the addition of carbonctte ash, which is principally from coal. While it cannot be said that they are definitely harmful, the better plan would be to mix them with vegetable rubbish to rot down before using in the garden. If there arc any harmful sulphides present, such as arc usually found in coal ashes, these will become broken down by the time the compost is dug in. Planting Beds.—l have a bed 00 feet long and three feet wide, with a three foot pongii fence in the middle with climbing roses along it. What can I plant along each side of the fenco that would be bright during the tennis season and will not bide the roses. A different kind could be used each side with a border along the edge. Also two large semi-circular beds, one with a good deal of shade. All the soil is good. I find your notes a great help.— J.W., Matamata. To advise on the planting of beds is of course to a large extent a guess In the dark, unless one actually knows the position, but however, tho following suggestions may be of use to you. For the long border one side could be planted with mixed phlox drummondii and the other with a good strain of mixed single petunia. For an edging use ageratum dwarf blue, lobelia blue, or the dwarf compact petunia, Rosy morn. For tho shady bed use Mimulus tigrinus with a border of Alyssum Little Dorrit; the other bed I presume gets plenty of sun and would be suitable for Dwarf French marigold harmony with a border of Tagetes pumila. Keep all tho seedpods cut off, as the flowers fade and tho beds should be in bloom for a lengthy period. Scientific Manuring.—lt has been claimed that by scientifically balanced manuring it is now possible to grow plants and trees almost entirely immune from blights and even insect

■ pests, as well as producing fruit far above tho average in mineral and vitamin content. 1 would bo obliged if you could give me particulars of any book on this subject, or suggest where up-to-dato information might be obtainable. "Commercial Orchard," St. Heliers. While scientific investigation has made great strides during the last ten years or so, we aro not yet in the position to bo able to do all that is claimed in your letter. A . much more potent factor in tho growth of plants than any combination of manures is the management of the soil population; thoso bacterial organisms which convert organic matter into soluble plant food. I do not know of any one book at present published which would give you what is required. Tho knowledge available is made up of gleanings from papers issued by research institutes and advisory boards ail over tlio world. If you arc interested in the subject, the hotter plan would bo to subscribe io "Scientific Horticulture," published annually by the Horticultural Educational Association, South Eastern Agricultural College, Wye, Kent, England. Leaf Scorch on Narcissus—Will you kindly let me know the disease affecting the enclosed daffodil leaves, also tho euro for the same? I keep cutting off the brown tips as they appear, using scissors dipped in a solution of formalin, but with very little success, as the ones cut. oflen die further back and many more affected leaves appear. I also sprinklo sulphur around the affected plan's. I have many very expensive bulbs and am naturally worried about it.—A.M., Warkworth. The disease is a fungus, stagonospora curlisii, commonly called leaf scorch from its appearance The trouble is not easy lo conlrol, hut can be kept, down lo reasonable proportions. Wet weather favours the spread of the spores and it is usually worst where the bulbs have been in the ground several seasons. The •spores lodge in tho scales of the bulb and tho leaves ore infected before they push through the soil. It was quite right to cut off the brown tips, but they should be taken low enough lo remove all infected tissue. In addition, spray with Bordeaux powder one ounce to one gallon at frequent intervals. Add one tablespoon of treacle (o each gallon of spray as an adhesive, as narcissus foliago is difficult to wet. When the flowers aro over give two or three good sprayings with Bordeaux before the foliage ripens off; this will prevent any spores travelling down to tho bulbs. Finally, lift Ihe bulbs and next season give a fresh position, which must bo well drained.

Choice of Sprays.—l rend with interest your notes and answers to queries and find them very instructive; there are a few tilings I wish to know if you will kindly answer in the usual way. (1) Is Bordeaux powder as effective as Bordeaux mixture when used ns a winter spray for pearlies and other trees. <'J) Is lime sulphur quite as effective as the above for winter spraying peaches, elr.f T found last season that when spraying potatoes with lime sulphur tho results were not very satisfactory. (3) Lupin seed sown this season

grew quite well up to six inches high, then some of the leaves fell off. On examination the leaves were showing small brown spots. Is this some blightP Sample enclosed. Situation is on an incline and not at all sodden by the heavy rains. Last season a small patch on the lower portion of the wilted and did not grow so well as those higher up the slope.— N.8.J., Ilclcnsvillo. Bordeaux powder is not quite as effective for winter sprays as the properly made Bordeaux mixture, but for summer sprays it answers the purpose quito well. The proper strength Bordeaux for winter use is: Bluestone, Gib.; hydrated lime, -llb.j water, 00 gallons. ('J) Liino sulphur is not so effcctivo as tho Bordeaux for winter sprays. As a rule lime sulphur is best for tho control of rusts and mildews, whilo for the general run of fungoid diseases tho Bordeaux will bo the better sjiray. It depends largely on what tho disease is; some are controlled by one spray and somo by another. (3) The lupins are showing signs of mineral deficiency, principally potash. If you apply sulphate of potash lo the soil at the rate of one ounce per square yard, a better growth will result.

Identification of Shrub,—l am sending vou a specimen of a treo. Would you kindly tell mo if it is a native,, and if so, tho Maori name of it?—" Native," Huapai. Native Shrub, Myoporum Laetum, Maori name, Ngmo Identification of Plant.—l have this growlng up strong in my orchard. Please let me know what it is and if it'is fit for cattle to eat?— Henderson. Plant is Cape Weed, Cryptostcmma calea I 15.7! 1,1 • Although it is not poisonous it is ol little use for stock. Identification of Shrubs.—Will you kindly tell me if specimen No. 1 is Dodonca purpurea, if so, how can it be propagated? Can you identify No. li, which I believo to bo a native?—" E.H.," Keri Keri. (1) Yes, Dodonca viscosa purpurea, but. not a very well coloured specimen. Propagated by seeds, there will be considerable variation in the seedlings. It is usual to pick out the best coloured ones and discard the Success is sometimes attained by cuttings put in in April. (2) Carpodctus serratus, nativo name Putaputuweta. Aspidistra Posts.—J have noticed on one or two leaves of my aspidistra somo white marks which 1 think is blight. Could you Please tell me how to treat the plant as I do not want all tho leaves to go the same, the white marks havo small black specks on 1 hem and it is on the undcrneaih part of the leaf. —"J.1t,." Ponsonby. Tho small black specks are probably scale insects, Ihesc suck out the sap and cause the white marks. Sponge the leaves frequently with soapy water to which has been added a little nicotine sulphate, one teaspoon to a gallon of water will bo enough. An old toothbrush is a useful implement to shift the black specks. Rinse with clean water afterwards.

Effects of Lime. —Will .vou kindly answer Hie following:—Will ordinary garden linio destroy the foliago of flowers and docs unslaked'linio burn only when wet' "Amateur. Auckland. Just what is meant by ordinary sard en lime? Wo have carbonate of iiino winch is simply ground limestone, slaked hmo is burned lime that has been slaked by either air or water mid quick or burned lime fresh from the kiln. Tho first two will not burn foliage but it is not advisablo to dust, it over too freely. Unslaked lime will burn at any time; if dusted over tho foliage it burns by extracting moisture from the foliage the process of slaking Violet Trouble.—Could you say what is wrong with violets. We have a long bore it" for S "verythbifc! ffl the edge of violets. The last two seasons they seem to havo gone right oft. hard y any left and very poor and 'iavo lifted thorn after flowering and planted crowns, but they will not como on. J 1 - 1 * the soil is done. Wo are 111 J llo r J' lLes using blood and bone three or fo ". r | im [ B a vear and it may be harmful to them, as this a suitable general manure as used, seeing that it is a general purpose plot? The violet stock would becomo exhausted in time when grown in a Kencra' nurpo&c nlnt The plants would do much better it Liven a place to themselves. The blood ant bono would not be harmful, it is a good general purposo manure. Tho volets "°" ( : however do much better on a diet of we decayed manure and leaf mould mixed w t.l the soil It is probably the lack of organic matter in the soil that is responsible for the failure. Phoenix Palm Falling.—l Iwvo a Phoenix Sinful. begiii'ning of hist summer. The fronds havo suddenly a deformity, the stems ahowijiK kii* l ks. l ea . s£ts C^o^g a S y tho bottom of tho trunk and theseb are ''kmußO bndlv twisted. I thought the trouble iiugm lie (inn to tho dry weather of last, summer, bSt with the wet weather it has shown no Improvement. Could yon advise of some method to save it. In some places on tho back of the deformed fronds there is a brown Pa A Itowl'n g' tho root's excessively drv would cause tho young tender shoo 8 down in tho centre to become deformed, to effect would not be seen until after Injurv to the roots thus jutting oil some'of the* water supply would also such a condition. The palm may recovc time if precautions are taken to seo that it never dries out completely. As young si 00 s are pushing from tho base there is hope for the plant. The roots of phoenix travel a long way and this is not always realised when digging near them.

Position tor Primula.— <i) Could .vou advise ine of the proper treatment for Primula sinensis. 1 am told they need a cool position, plenty of fresh air and not too much water. Would the grate of an open fireplace be m suitable position? I have a healthy looking plant in a tin four inches square. Should it be repotted? When is the best time to do this and what manure if ati.vP (l?) Would onions grow in soil that is approximately six inches deep? (3) I havo two climbing roses, Lemon Pillar and Climbing lfose Marie. These hove become infected with a white scale with a black spot 111 the centre. Can yqu identify this and indicate treatment if possible? Primula," Thames. The fireplace would bo too far from the r 11 draughty. A window where the full sunshine does not strike 011 the plant would be better. The plant should be repotted now into & receptacle at least six inches in diameter to produce a good flowering specimen Use turfy loam three parts, old dried cow manure well broken up one part, with a little coarse sand. (2) Onions require a deep soil as UlO first consideration, for the roots go straight down. They are hardly likely to be successful in six inches. Tho bulbs will be small. (;i) The insect is rose scale and the plants should be sprayed with white oil at two per cent strength during the next few weeks. Apply another spray about a month after the first.

Brown Rot o» Peaches.— ii) Will you tell inc how !irnl when to spray for brown rot. on peaches and apples. 1 understand a mixture of colloidal sulphur and lime sulphur is used. Would one tablespoon be mi ounce? Kindi.v advise me of the three most important times to .spray as it is impossible for me, to do litem all 1 have a Cox's which was affected with brown rot like the peaches. T cannot find any cankers on tho tree. CJ) I have peas reaching the bearing stage and rotting at the base of the stalk. They are planted in newly trenched ground and Ihe seed was taken from a successful crop elsewhere. Another \nriety did the same last year. This is happening to my flowers also.—"Brown Hot," Papakura. (1) Spray before the buds burst with Bordeaux O-l•oO, after petal fall, lime sulphur four ounces to each four gallons of water plus half an ounco of colloidal sulphur. Repeat in January, twice if possible. A tablcspoonful is approximately one fluid ounce. There are possibly cankers overlooked, if there nro none visiblo infection will not bo so bad Last season was exceptional!} bad for brown rot on apples. C2) The trouble with the pens is near wilt or root rot. Your soil is evidently infecled with the organism which causes it and as it. can he carried in drainage water it may have como sonu distance. There is no reliable remedy other than the breeding of wilt resistant strains. Excessive soil moisture favours the spread of this disease, so that a very well drained soil is of paramount importance for early crops.