Is this tuna can hack safe for my geraniums?

A reader put liquid from their tuna cans onto some old pots of geraniums. Within a week they began blooming and looking healthy. Has she discovered a new plant remedy?

Pig Face pink succulents make brilliant ground cover in hot, dry, sandy and salty environments.

There are dozens of native plants with edible berries that you can easily grow at home, even in a small garden or in pots. Midyim berries (Austromyrtus dulcis) are sweet with a eucalyptus tang; they grow on a small shrub that can be clipped into a low hedge.

Muntries come from a spreading coastal shrub, Kunzea pomifera, that tolerates sandy soils and salt. The purplish, crunchy berries are higher in antioxidants than blueberries. Karkalla or pigface (Carpobrotus, pictured above) is a fleshy succulent that makes a brilliant ground cover in hot, dry, sandy and salty environments. The fuchsia-coloured flowers are followed by small red fruits that have sweet pulp and salty skin; the leaves are edible too.

Atherton raspberry (Rubus probus), unlike exotic raspberries, thrives in warmer climates where it fruits in summer and autumn. Growing it in a pot keeps this vigorous bush in check.

Others include ruby saltbush (Enchylaena tomentosa), a succulent with salty-sweet small berries; blueberry lily (Dianella revoluta), a common garden plant; blue tongue (Melastoma affine) with sweet black berries; and wild currant (Antidesma erostre), a tropical shrub with highly ornamental, grape-like clusters of berries.

Local delicacies – give them a try

A wide range of edible native flora, from fruiting plants to vegetables, nuts, seeds, herbs and spices, is available nationally under the Tucker Bush label.

Atherton raspberry.

Muntries.

Stockists and details at tuckerbush.com.au

Midyim berry.

Blueberry lily.

Q&A

I happened to put the liquid from tins of tuna onto some old pots of geraniums. Within a week they began blooming and looking healthy. Have I discovered a tuna tonic for plants?

Jacquie McCoy, Kotara, NSW

Tuna in brine or oil would be bad for the soil and plants but in spring water should be fine. Fish is routinely used in fertilisers to add nutrients; the difficulty is knowing the concentrations – too much can be fatal. Use it no more than monthly, with plenty of water between times.

My bay laurel hedge is looking bad with assorted insects and sooty mould. How do I get rid of both?

Jillian Boyd, Armidale, NSW

Sooty mould is a fungus that grows on the sticky honeydew exuded by sap-sucking insects, usually scale. Thick coatings can inhibit photosynthesis. Treat the pest first and the sooty mould will flake or wash off. Spray foliage with a horticultural soap to help loosen it before rain. Prune off the top of the hedge to increase air flow, light and access for predators inside the hedge. Improve plant health with water, fertiliser and mulch. A thorough spray with PestOil or Eco-Oil treats young crawlers but won’t kill adult scales. Repeat after two weeks. You can buy parasitic wasps and predatory insects for scale at bugsforbugs.com.au.

How can I strike grevilleas from cuttings?

Phill Jenkins, Yeppoon, Qld

Grevilleas can be tricky. Take 10cm-long semi-hardwood cuttings from the non-flowering stems of a healthy plant. Remove the lowest leaves; roots form best from just below a node. Scrape a sliver of bark off both sides of the base, dip in rooting gel then place into propagating mix. Cover with a plastic bag; bottom heat is beneficial.

Send your questions to [e-mail]. The best question for October wins Fiskars’ PowerGear X Large Bypass Lopper, designed for strength and comfort, worth $145. fiskars.com.au

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