Gardeners’ queries

Press, 15 October 1976, Page 8

Gardeners’ queries

My four-year-old daphne bush did not flower this year although It did so last year. Should It be pruned after flowering? I can find no reference In gardening books as to whether it should be pruned, when or how. The branches have become long and untidy. — (Christchurch). There has been a marked lack of bloom in daphnes tins vear which can probably be associated with the climate during the past few seasons. The best time to prune Daphne odora, which is presumably the species being referred to, is during and after flowering. Old leggv specimens should be carefully cut to the lowest desirably placed bud. Following bud breaks lower down more severe cutting may be deemed desirable. A check of two books on shrubs has indeed revealed that little is said about the pruning of these plants. I have a garden with azaleas and lilies. My problem is that the garden is becoming heavily infested with sorrel which Is very difficult to get out from among the bulbs. I know lime will help to control it but the above plants do not like lime. Is there any other way to control it? You once had a query from someone who wanted to know what an inch plant was. Enclosed is what I have been told is such.—"B" (Reefton). Sorrell can be difficult to eradicate and as you have stated it has no affinity for lime. It also tends to spread on lighter, heavily cultivated land. Apart from liming or the use of basic superphosphate, the building up of soil organic matter content and the use of mulches can assist in its control and eventual eradication. It is suspectible to the application of amitrole-T and dicamba either alone or mixed with McPa or 2,4-D.

We have a new section to be put down In lawn. I would be most interested to have your views on using Mercury Bay weed or dichondra instead of grass — "L. 8. (Blenheim).

A dichondra lawn is formed either by the insertion of plugs (plants) into the soil or by seeding. It is very essential to eliminate all weeds from the area beforehand because subsequent control after the establishment of dichondra is not easy. This type of lawn requires moisture, “gives” to tread, and cannot be recommended for hard wear.

My query Is about an apricot tree which has always had a good average crop. Last year it didn't have any and I blamed the last frosts, but nil this season, so enclosing a sample.—"M.B." (Scargill). Disease, frost and prevailing weather conditions at blossoming time are the major factors which may inhibit the setting of apricots. This season there has already been at least one frost severe enough to damage the flowers, and conditions both this, year and last year have not been conducive to good pollen transference. The samples were too small to decide any positive answer.

I have a Hoya plant growing in a Sin-diameter clay plot. It is situated on a window ledge where It gets part of the morning sun. The plant is 10 years old and has been repotted onee. It flowered beautifully for six years, but for the last four, although appearing very healthy and growing lots of new leaves it has not flowered. Is there something that can be done to make it flower or is It finished? I give it a good soaking once a week.—"E.B." (Christchurch). Of all popular house plants the Hovas tend to provide the most variable response to a range of conditions and treatment in the endeavours to get them to flower consistently well as far as personal experience is concerned. It is noticeable that Hoya camose tends to flower more prolifically where the plant looks somewhat “anaemic,” that is, the foliage is pale in colour and growth is not at all rampant. For this reason It is best to keep them under-potted so that they become almost root bound. Over-watering should be avoided and although plants should be kept in light situations, direct exposure to the sun, particularly through glass, should be avoided. Could you please advise the most satisfactory method of storing carrots? Last year we dug them in a hole in the garden, but found we lost such a lot by rotting. Is this unavoidable, or can they be covered with something before soli? — V.C. (Christchurch).

Carrots can be stored for several months under suitable conditions. Where drainage is good, and the soil is not too heavy, carrots can even be left in the ground for some time and dug as required. Soil is unsuitable as a covering for stored roots, and the most usual thing is to place them In moist sand in a cold but humid place. It is very important to ensure that all the carrots that are to be stored are lifted with care to avoid damage and that only perfectly-sound ones are retained for this purpose.

I have lust purchased a gum tree called Tristania laurina (water gum) which is not listed in any of our books. As we thought It may not take our hard frosts out here we have delayed planting it out. We purchased a variegated holly with lovely red berries, but every year since it has flowered but never berried again. So we got a new tree full of yellow berries which the nurseryman claimed would pollinate the first one, but still no berries. In Papanui North some variegated holly trees about ISft high are not carrying any berries either. Is there a trick to get them to berry? To get a crop of fruit from feijoas they say to plant two. Does this mean two of the same, or different varieties? — "Belfast Peg" (Belfast). Tristania belongs to the same family as the gum trees but is not one of them. The species you refer to is also commonly known as kanooka and is more resistant to frost once it has become well established. Whether it will survive heavy frosts is debatable, although it will regenerate if the root remains alive. It forms a very attractive tree which is well worth cultivating but is intolerant of too dry conditions for long. Most hollies are either male or female plants, although there are a few which carry both sexes. This, however, does not apply to variegated forms. Male plants do not bear fruit. Although it is often said that there are enough male plants around to ensure pollination, this may not be the case, and even if it were so, prevailing conditions could influence subsequent fertilisation of the female flowers. Grafting a male scion on to one of your plants would solve the problem. The species. Feijoa sellowiana requires to be planted at least in pairs within a reasonable distance from each other to fruit consistently and this applies to some but not all the cultivars as well. However, because of some cropping variability even then personal advice is to plant two if possible.

Could you tell me the name of the enclosed camellia? Also, is It possible to grow it from cuttings? If so, when would be the best time

to try this? — E.P. (Christchurch). It has not been possible to identify the camellia. Camellias can be propogated in a number of ways, but cuttings probably represent the least involved. It is also the method with the widest application to the different species and cultivars. Semi-ripe to ripe shoots, about 10-15 cm long, should be inserted in sharp sand and kept moist. The time to take them is towards the end of the year and early in the new one More details will be presented in a forthcoming article to appear in due course. Now that arsenate of lead Is no longer obtainable, what should I use as a substitute for the control of codling moth on apple trees? — "Willie" (Chch). Carbaryl is much used in the home garden for codling moth control but this has two shortcomings—one of which is that if used within four weeks after petal fall it can cause considerable fruit drop, more so with some cultivars than with others. Second, it has a very short residual life, with a waiting period of only one day. This latter aspect has an advantage close to harvest as it enables good protection until picking time. Maldison is recommended in some circles but personally excellent results have been obtained by using a 50 per cent diazinon wettable powder. This has a good residual life hut a 14-day waiting period.