Garden queries

Press, 29 January 1988, Page 14

Garden queries

1) Two specimens of the enclosed shrub, 10 years old, have tended to make little new growth and rather become bare and woody. 2) Can you identify the two weeds one of which is growing in the driveway while the other appeared lor the first time on the road verge. Could you advise what to do to make the shrubs grow, and secondly, what spray to kill the weeds with? J.M.(Waikari). 1) Specimens of Euonymus have been noted to appear as if they are stagnating, for want of a more apt description, with moss and or lichens frequently present under such circumstances. Pruning, moisture, and an application of a fungicide if mildew is present, often sees such plants back into normal development. 2) The prostrate weed is prostrate amaranthus, which is currently proving somewhat resistant to herbicide treatment. The other tall-growing plant is wild mignonette which is susceptible to dicamba plus 2,4-D. For many years we have grown the Telegraph cucumber without problems but for the last two years at our new home, this has changed. We are finding that nearly all the fruit has a marked bitterness from the growing end as per sample. All the male flowers are removed and the plants are fed with a liquid solution of potash, Epsom salts and urea where we have previously watered with liquid horse manure. We had been told that an over-supply of nitrogen as well as pollination by bees can cause this bitterness to occur. Hoping that you can throw some light on this problem. “Too bitter”(Chch). Although bitterness in glasshouse-grown cucumbers can be attributable to cross pollination, the English Telegraph types are predominantly parthenocarpic, which means that they are capable of producing fruit without fertilisation; recent Dutch releases are even more strongly all-female. Other factors associated with bitterness include Avreqqive nitrneen availabil-

ity, and too low and variable temperatures. There is also a tendency for bitter fruit to be produced towards the end of a plant’s useful productive life. It should be noted that urea is a highly concentrated, rapidly available source of nitrogen, of 46 per cent total weight as against ammonium sulphate which is 21 per cent nitrogen. The percentage elemental content of a fertiliser must be taken into account when considering substituting one form for another. Other considerations are its possible suitability for the plant concerned, and the speed with which it becomes available to the plant. I agree with G.B.(Chch) about your helpful advice through your column. May I also offer a suggestion regarding suckering trees. We had this problem with a lilac coming up through a crack in the concrete so we tried pouring kerosene on the suckers and it killed them. We now do this to any that come up in the garden as well and no harm has come to the tree. Another tip, for what it’s worth: I dislike using sprays so for small areas I use aerosol fly spray and it does the trick, but don’t use it too close to plants in the sun. M.C.(Ashburton). Thanks for the tips and alternative methods. Suggestions from readers are always welcome as innovative ideas can often benefit others. If using kerosene on grassed areas care must be exercised to avoid spillage as it will adversely affect the grass. Fly spray contains one or two organic materials such as permethrin and pyrethrum which can be obtained as formulated insecticides, either as emulsions or as wettable powders specifically for the control of some plant insect pests. Gardeners’ Queries should be sent directly to Mr Mike Lusty, 56 Wayside Avenue, Christchurch 5. Samples should be separately wrapped in a plastic bag with air holes. Provide representative, good-sized samples, and your name and address. A nom-de-plume can be used for publication.