GARDENERS’ QUERIES

Press, Volume CXI, Issue 32702, 3 September 1971, Page 17

GARDENERS’ QUERIES

Could you please give some information on the Australian native heath and whether it will do ail right here? Where can it be obtained as nobody seems to even know about its?—S.B. (Christchurch). The genus Epacris is generally called Australian heath, and is referred to as native fuchsia also. This particularly applies to the species Epacris longiflora which grows about three feet high. Under suitable, conditions the long scarlet-tipped, white, tubular bell-shaped flowers, which hang in pendant rows from the slender branches, appear for most of the year. The poorer soils, even sand, suit them best, although they will grow quite successfully in well-drained heavy soils; they are intolerant of alkaline conditions and respond to annual pruning. The Epacris generally provide excellent cut flowers. Plants are not much offered for sale in New Zealand. Enclosed a number of leaves from our matipo bush which is about six feet tall and is generally of this appearance all over. Is this as it should be or is

It in some kind of trouble? —Local Gardener (Christchurch). The pitting or puckering of matipo leaves, such as on your Pittosporum crassifolium, is usually due to the activities of young chennids which normally feed and remain in one place until they reach the adult stage. Their presence is often accompanied by the appearance of socalled sooty mould fungus. Lindane or lime sulphur are alternative controls which can be applied at any time other than when the plant is in flower, the best time being in spring. More than one application during the year may be necessary. I am enclosing a cutting taken from a hydrangea. The blight ha* afflicted several of these shrubs

especially those situated in a cold damp part of the garden. I should be very pleased if you could iden-

tify the trouble and advise

the best way to combat it—N.E. (Christchurch). This is a recurring query and suggests just how prevalent this problem is in local gardens, at least. The white deposits are scale insects and good control can be achieved by spraying at least twice with summer oil or lime sul- ‘ phur at this stage of growth. ’ lam intending to clear ' a section of my garden - and establish a bed with ) camellias, rhododendrons i and azaleas. I would appre- . date your opinion on the 5 following questions. (1) Is , ammonium sulphate satis- , factory to give the soil an ; acidity; if so, what , strength would you use, . and if not, what Is a better agent? (2) When is J the best time to plant the . respective shrubs? (3) . Could you give me some ’ idea of the growth rate of ' these plants? I envisage . camellias as the main and ’ tallest background with J small rhododendrons in ■ front and azaleas in the ' foreground —D. (Christchurch). If you want to strictly “follow the book” then a soil acidity test is the best way to go about preparing an area for plants which require acidic conditions to do well.

Thia is definitely the requirement for growing good rhododendrons which thrive at a pH level of around 5.5. Iron sulphate, which is quick acting, or sulphur which is very slow, are the two most-used minerals for increasing soil acidity. To bring a pH reading down from 6.5 to 5.5, approximately 121 b of iron sulphate or about 14Jlb of sulphur should be applied per 100 square feet of ground. Peat is also an excellent addition to the soil for such plants as rhododendrons. It is not feasible to suggest possible growth rates as so much depends on. prevailing circumstances, but during the first year or two there is often very little made. Spring is an excellent time of the year for most plantings of trees and shrubs.

I have a greengage tree which is covered in blossom each year but does not bear much fruit. I have sprayed it with a strong solution of sugar and water and this has improved the crop to some extent Can you please advise me if it is necessary to hang the blossom of another greengage in the tree or will some other variety of plum do?—A.S. (Christchurch). Although the provisions of an attractant to bees in the form of sweet syrups are fairly popular in order to achieve cross pollination it is really a rather hit and miss procedure. The greengage is self-sterile and there must be a suitable cross pollinator in its vicinity if it is to crop well: Coe's golden drop, Grand Duke, Washington gage and Angelina Burdett are suitable. The best thing is to have one of these varieties growing near by, but grafting would also suffice. The placing of a flowering branch from one of the abovenamed varieties in the greengage tree is also a reasonably successful method of ensuring cross pollination. Could you tell me what is wrong with my potatoes? They look quite good from the outside but when you cut them there are black spots all through them. I would be pleased if you could advise me so as I do not have the trouble this ; season. A.H. (Christchurch).

It would be necessary to see the tubers concerned before venturing an opinion as there is more than one trouble displaying similar symptoms. In the meantime

do not use any of the crop for seed this year. Gardeners’ queries should be sent direct to Mr M. Lusty, 32 Brockworth Place, Riccarton, Christchurch 1. Any specimens sent for identification must be securely wrapped to ensure that they arrive in recognisable condition.