The hibiscus shrub, in its many gorgeous varieties, was never more popular than now. It came first from the tropics, and so needs protection against frosts. Flowering time is 3 months in Melbourne and almost 6 months in warmer parts. It does best of all by the sea.
How to care for a hibiscus plant
Hibiscus bushes can be planted all the year round out of containers. They need well-drained soil and like to be watered often.
Don’t put them among other shrubs so that they have to compete for food and light.
Preparation of the hole is important. Dig it about twice the size of the container in which you bought your young shrub.
Fork the soil in the bottom of the hole, but if you have heavy, clayey soil don’t dig into the subsoil, as this would result in water lying at the foot of the plant, causing possibly fatal collar-rot.
Mix 1 or 2 shovelfuls of rotted cow manure, fowl manure, or mushroom mulch with the soil you have taken out of the hole. Cut the tin down both sides. Put a shovelful of mixed soil back in the hole, lift the plant gently from the tin, and place it in position.
Fill in around the roots with the rest of the mixed soil and press lightly.
This is the time for pruning – usually the first weeks of September. Cut back well-grown hibiscus shrubs about one-third all over.
Trim the shoots just above a node or leaf-bud that faces toward the center. Always use sharp secateurs. When the young shoots have sprouted about four inches, pinch out the tips; when another sprouting of about two inches grows, pinch the tips out again.
After pruning, fertilize the shrub well with cow manure, fowl manure, or mushroom compost.
In October or November do it again with a complete fertilizer, but don’t be heavy-handed. Spray with Malathion, Wellspray, or Albarol (white oil).
The aphis and the hibiscus weevil are the worst enemies.
The shrub should be growing well. Apply a little more fertilizer now, preferably Nitrophoska.
Do this monthly if the weather is dry, fortnightly if it’s wet.
A mulch of leaf mold, straw, or mushroom compost keeps the sun’s heat from the roots in sandy soil and aids in retaining moisture and preventing bud-drop and leaf-drop.
Keep the mulch away from the trunk of the shrub to guard against white scale or damp off at ground level.
The best blooms come in the autumn, so give light applications of complete fertilizer every 2 weeks. Moreover, fertilizer at this time of year builds up a supply of food to keep the shrub going through winter.
Don’t feed or cut your hibiscus during winter. Wait until spring.
A spray of Isotox, Chlordane, and Zineb every 2 months will be sufficient (they are compatible for mixing together).
Be sure to water the shrub at least 3 hours before spraying or fertilizing.