Garden tips: killing weeds; lemon leaves; cycads; fertilising natives

Pull persistent weeds out little buy little, or smother them in paper and mulch.

A Sweet Spot ‘Yellow’ rose.

The trad (wandering jew) that rampages, despite my best efforts, under my bay tree got frostbitten this winter. How can I finish it off? My husband wants to use butchers’ salt, but won’t this kill the bay tree? - PAM ATTWOOD, BY EMAIL

Salt will not only kill the bay tree, it will ruin the soil for years to come. Last week’s advice for a similar weed was persistence in pulling out every returning fragment. Chooks are excellent at this. Or smother it with newspaper (about eight sheets thoroughly wetted) under mulch. Weedicides are not very effective on this fleshy weed.

My mature lemon tree crops well but these past months has dropped masses of leaves, most yellowing. It’s now blossoming with new leaf growth. Is this normal? - RICHARD EASTWOOD, BY EMAIL

Lemons often shed their older leaves as they flush into new growth in spring. Yellow leaves are common in winter too, as cold temperatures mean citrus don’t efficiently take up nutrients. Leaf drop is a symptom of waterlogging, but if new growth is vigorous it’s probably fine. Fertilise citrus now, and lightly each month, with a chook-poo-based fruit-tree fertiliser.

What fertiliser is best to promote growth of young native plants before our hot, dry summer? I also have tubestock ready to plant. - ALAN EAST, COOTAMUNDRA, NSW

Native plant fertilisers should have less than 2 per cent phosphorus. Controlled-release Osmocote Native Gardens and Acticote Natives are safe and long lasting. Garden Gold for Australian Natives also contains a wetting agent. Troforte M Native Landscape Planting Tablets contain slow-release minerals coated in beneficial soil microbes. Avoid mushroom compost, sewage sludges, poultry manure and rich composts on natives. For all fertilisers, follow the label directions precisely and water after application.

When my cycads develop new leaves they are curly and eventually go brown and die. What’s causing this? - HELEN BRADLEY, PERTH

Frizzletop commonly occurs when the soil pH is high, making manganese unavailable for plants to take up. High phosphorus levels do the same thing. To acidify the soil back to the ideal 5.5-6.5, add sulphur, but note this takes time to work. For short-term improvement apply a solution of manganese sulfate and liquid fertiliser over the leaves monthly for three months.

Flora: Sweet Spot roses, from the same stable as the highly successful Flower Carpet roses, have just been released. This distinct group of roses features abundant blooms with dark-coloured centres and medium fragrance on a compact bush. The first two colours are ‘Yellow’, which is golden yellow, and ‘Calypso’, with bicoloured pinkish red and yellow flowers. They reportedly flower almost continuously from spring to autumn, with the blooms changing colour as they mature, giving a multi-coloured effect. Billed as decorator roses and growing about 60cm high and wide, they work well in pots or in groups in the garden, even as a low colourful hedge. A sunny position is best. Recommended pruning is to trim back by half, once a year.