Root causes of sewer pipe trouble require expert opinion

If you think a tree on council land is playing havoc with your sewer pipes, read on.

‘Coral magic’ crepe myrtle is a new shrub-sized variety of the tree.

Every year I spend hundreds of dollars clearing sewer pipes blocked by a mature Ficus on the council’s verge. They claim there is no evidence their tree is to blame. What can I do?

LUISA MORRIS, PERTH

A consulting arborist may be able to visually confirm Ficus roots as they have distinctive lenticels on thicker roots. Otherwise, laboratory DNA sampling is used to identify tree roots in legal cases. With no facilities in Perth, contact the plant pathology unit at Royal Botanic Gardens Sydney for instructions on what and how to send samples. It costs $330 for the first specimen. You might need to replace fractured pipes. Root-control tablets flushed down the toilet might help.

Would a jacaranda grow in a large container about 1km from the beach?

DION MURDOCH, ENCOUNTER BAY, SA

Jacarandas grow well in your area but they’re not well suited to growing in containers. They develop large and spreading roots close to the surface. Nurseries grow them to flowering size in growing bags of 75-120cm diameter but it’s a specialised skill. They need machinery to move them and trees need to be planted out to keep growing.

After a period of rainfall, do plants need to be regularly watered? Is there a danger they could get waterlogged?

STELLA LOMBARD, SYDNEY

How quickly water drains from the soil depends on the type and depth of the soil and subsoil. Sandy soils drain rapidly; clay soils retain water; loams are somewhere between. Shallow-rooted plants such as young vegetables need frequent watering, whereas deep-rooted roses and trees survive long periods of dry. Get to know your soil by digging deep holes in various spots.

The two glory vines (ornamental grape) across my north-facing veranda provide shade and look good but in the past two summers the hot, dry winds rip off the leaves. What could I plant instead? I’m on tank water.

VANESSA NICOLLE, MARGARET RIVER, WA

There’s a limited choice of waterwise, tough, deciduous climbers to give summer shade and winter sun. Wisteria, cape honeysuckle (Tecomaria capensis) and pink trumpet vine (Podranea ricasoliana) are possibilities but all can become thugs. Evergreen Banksia rose and bougainvilleas should also thrive. Glory vine is usually tough enough; assist it with Saturaid and mulching. Spray-on Droughtshield gives foliage a protective polymer coating.

Send your questions to: [e-mail] or Helen Young, PO Box 3098, Willoughby North, NSW 2068. Web: helenyoung.com.au. The best question for January wins a set of five elegant, magnetic vases for your dining table, worth $72.95, from Independence Studios (isgift.com).

FLORA

Reading Great Gardens of London (Murdoch Books $60), overcame my first notion that it might have limited appeal. Victoria Summerley has a knack of avoiding the usual rote description of a garden, weaving history and fascinating anecdotes of people and places into her text. If you’re planning a London visit, be sure to savour this book first; if not, it’s still a pleasure for armchair travellers. Some of the gardens are open to the public, others are revealed only in books like this. Number 10 Downing St and Clarence House are among those in the Pomp and Circumstance chapter. Wild in the City gardens include the floating barge gardens, and the exciting new landscaping of the former Olympic venue. One of my favourites to visit, the 0.6ha Kensington Roof Gardens, complete with flamingoes, stream and woodland, features in the chapter on High-Rise Retreats. The many photographs by Hugo Rittson Thomas and Marianne Majerus are superb.