Gardeners’ queries

Press, 7 September 1984, Page 15

Gardeners’ queries

GARDENING

by

M.Lusty

I wish to plant a bougainvillea against the house, but have been told that it can disturb the foundations with its roots. Wouldyou comment please? M.M. (Wellington). There should not be any danger to reasonably solid foundations by planting a bougainvillea close by.

We have a young Paulownia tomentosa growing in an open part of our section. Because it gets a lot of wind the tree is not growing properly and we would therefore like to replace it with something of similar shape and size, preferably evergreen. A.T. (Westport). Because of the unknown factors involved, and the desire to have a substitute of similar conformation, it is only possible to make some token suggestions as follows. Cornyocarpus laevigatus, Banksia serrata, Meryta sinclarii, Pseudopanax laeteus and P.arboreus, Griselinia lucida.

My tiny photinia has been growing extremely well until the last three weeks or so, when all the young growth has suddenly started to curl (as enclosed). It is exposed to wind and we had a very cold spell recently. My frangipani which is now growing indoors tends to shed its leaves as soon as it gets more than a couple of them — it now has a shoot and one leaf. 18. (Sumner). It is possible that the early symptoms of fire blight have infected at least some of your shrub but this cannot be substantiated from the samples enclosed. The leaves infected by this bacterial disease tend to assume a scorched appearance, but continue to hang from the branches which gradually die back from the tips. Control is often achieved by cutting back well below the last visible signs of infection. Spraying with streptomycin provides an expensive form of control and the application of zineb is said to nave some effect Check on the drainage as well as the amount of water given — over or under watering is a common fault But the damage could already have been done and the plant is suffering symptoms of root rot.

Could you please tell me the reason and remedy, for the loss of leaves on the hebe twig (half the bush is like this) and

also for the affected leaves on the pieces of the other two shrubs. CJH. (Chch). Caterpillars are eating the leaves of the Euonymus japonicus “Variegata Aurea” and the Choisya ternata, and the spraying of both of them with acephate should give good control. It looks very much like only the spent flowering tips have been provided as specimens from the hebe, and as these stems were virtually bereft of leaves there was unfortunately nothing really on which to make a diagnosis.

About three years ago I planted two dwarf conifers. They have developed well until recently when the leaves of one started to turn brown as in the enclosed sample. The leaves of the second one are

also showing some form of decay. Could you advise the treatment necessary to restore the plants to a healthy condition. E.C. (Chch).

The Chamaecyparis argentea compacts is affected by what is commonly called cypress canker. A suggested treatment is to apply a mixture of a copper based material plus a little summer or all seasons spraying oil. The other cypress indicated the presence of caterpillars and thorough application of acephate should overcome this problem. It would probably be worth combining the two separate controls and applying the mixture to both plants. It will be advisable to repeat the application within two to three weeks.