Treated pine in the veggie patch

Tag : Vegetable Garden Gardening Organic Vegetables

Should I frame vegetable beds with treated pine?
(Dave James, by email)
The CSIRO's fact sheet on copper chromium arsenic-treated timber ( www.csiro.au/content/pt24 ) reviews the scientific research, which identifies extremely smallrisks from leaching of arsenic, which also occurs naturally insoils. Within 100mm of treated timber, slightly elevated levels canoccur in root vegetables, but in a form considered non-toxic tomammals. You can paint CCA-treated timber with a waterproof sealantor use heavy plastic to separate it from soil. Alternatively, usealkaline copper quat or copper azole-treated timber or hardwood.
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Since a hatchet job three years ago, our previously glorious goldenpenda (Xanthostemon) has hardly flowered. Other local specimens arewonderful, so what can we do?
(Elizabeth Kime, Yamba, NSW)
Golden pendas respond well to pruning and may be kept small withlight annual pruning, even formed into a hedge. Yours may still berecovering or in too much shade. It is a rainforest tree, so keepit well fertilised, watered and mulched.
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Please suggest something low, evergreen and flowering to plant infront of gardenias, backed by ornamental pear trees, in a sunnybed.
(Ashley Lewis, Perth)
For strappy foliage try dwarf Agapanthus 'Snowball' with large,white flowers or variegated society garlic (Tulbaghia violacea).More informal is Convolvulus cneorum with soft, silver foliage andwhite flowers or Evolvulus 'Blue Sapphire' with blue flowers.Tricolour star jasmine doesn't flower but the pink, cream and greenvariegated foliage is just as colourful.
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My huge sasanqua camellia has small, yellowish leaves and recentblooms withered. I've fed, watered and cut out dead twigs. Is itdying?
(N. Havea, Bendigo, Victoria)
The root rot fungus phytophthora could be the cause. Yates Anti Rotis the best treatment, although badly affected plants are difficultto save. Do not fertilise sick plants, however Seasol can helpstrengthen roots. A soil pathology test (about $100) would providea definite diagnosis.
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FLORA
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