In this week’s Question Time, Don was asked about white curl grubs and chrysanthemums.
White curl grubs
Q: Mark from Padstow Vale wanted to know how to deal with large numbers of curl grubs in both his lawn and garden beds.
A: White curl grubs are the larvae of scarab or cockchafer beetles. (Some people also call them witchety grubs, but they are not witchety grubs.) They are C-shaped, whitish grubs with orange heads. They feed on plant and lawn roots and do a fair bit of damage, particularly when they are in pots. The problem can be worse in gardens that are lit up at night because the lights attract the adult beetles, which fly in and lay their eggs.
If you have magpies or blackbirds in the garden they will dig up the curl grubs and eat them. If you spray with a pesticide to control curl grubs, the birds might be poisoned too. Don simply recommended fertilising and watering well (water restrictions permitting). Some people use a product called Professor Mac’s 3-in-1 for Lawn and Garden. It is an organic insecticide, fertiliser and wetting agent. It costs around $11 for 1 litre, or $15 for 2 litres with hose applicator.
Q: Kay from Maryborough has 125 chrysanthemums. She wanted to know if chrysanthemums should be dug up and moved after they have been in one spot for a long time.
A: You can dig up and divide existing clumps of chrysanthemums (Dendranthema x grandiflorum) in early spring. They can also be grown from seeds or cuttings. They like full sun and well-drained soil. Water well through summer and feed with liquid fertiliser every four to six weeks to encourage strong growth. For a compact bush, tip prune young plants to encourage branching.
Potted chrysanthemums last for several weeks indoors if watered when dry and kept in a well-lit spot. Remove spent flowers and discoloured leaves. After flowering either discard, or cut back to about 15cm (6″) high and plant outdoors in a sunny, well-drained spot.
On Mother’s Day Australians traditionally present their mums with a bunch of chrysanthemums. Chrysanthemums are naturally in season in Australia in autumn, so are cheap and plentiful in time for Mother’s Day. There are many named cultivars of chrysanthemums. Colours range from white to pink, purple, yellow, bronze and everything in between. Flowers come in all shapes and sizes.