Olive plant may lack nutrients

Shrivelled leaves and yellow spots appeared on my Japanese olive plant after a mealy bug attack, though that seems to have cleared up since I moved the plant into full sun. It is potted in an airy matrix, and I water it twice a week. What can I do to make it healthy again? 

Jeanette Poon

Your olive plant’s leaves look chlorotic and misshapen. It seems to lack nutrients.

The plant’s gritty, well-draining growing mix is good for aeration but does not retain nutrients well. You may want to add slow-release fertiliser pellets to the root zone, which will be a better method of nutrient delivery. Select pellets containing both the major nutrients and trace elements, which provide essential micronutrients.

Foliar fertiliser, which is formulated for spraying onto leaves, can also be part of your growing regimen.

Ficus may be infested with scale insects

What is wrong with my plant?

Chok Ken Sim

Can you scrape the brown particles off the leaves? If you can, your Ficus plant is probably infested with scale insects, a type of sap-sucking pest. An infestation of this severity will be difficult to manage, due to the amount of pesticide needed and the large surface area that has to be treated.

Consider pruning your plant so you have fewer pests to deal with, and add dinotefuran granules at the root zone. These granules are a form of pesticide designed to kill pests that suck plant sap. Combine this with regular and thorough applications of summer oil to coat and suffocate pests on the leaves.

Orchid needs humid environment to thrive

I have had this Dendrobium for a few years. When I first got it, it was flowering with leaves at the bottom, but these have since shed. Overall, the plant looks weak and emaciated. Can I revive it?

Chow Mun Zing

Your orchid is not a Dendrobium but a Vandaceous orchid. It looks like it is drying up. Has it been kept in a hot or dry location?

As this type of orchid has exposed roots, give it a moist and humid environment so it does not get dehydrated.

The strap-like leaves indicate that it is an orchid species or hybrid that grows best in a semi-shaded spot.

Plant may need to be restarted from new stem-cuttings

I have an old plant with perfumed flowers that needs to be rejuvenated. I have been adding fertilisers such as chicken and goat droppings, eggshells and liquid fertilisers, but the plant still looks like it needs a pick-me-up.

Arumuganathan Ramanathan

Your plant appears to be old, with pruning cuts that have healed poorly.

A plant of this age may not respond well to the methods you have been attempting. You may be better off taking stem-cuttings from it and rooting these to start new, healthier plants.

Check if the soil is compacted or poorly drained. The latter issue will not be easy to remedy. If the soil is compacted, you may want to incorporate good-quality compost into it to improve its structure. Do so carefully to avoid damaging the roots.

There also seem to be brown bumps on the plant’s branches. If you can scratch these off, they could be scale insects, a type of sap-sucking pest common on woody plants. You will need to spray summer oil regularly and thoroughly to kill them.

Damaged fruit will ripen prematurely

My bitter gourd plant seems to be growing well, but the fruit are short and turn yellow overnight. Do you have any remedies?

Thomas Lee

There is a damaged patch on your bitter gourd fruit. Note that fruit will ripen or be aborted prematurely if they are damaged. You will probably need to wrap the developing fruit in a protective bag designed for this purpose.

Also, ensure flowers are pollinated properly by making sure you have natural pollinators, like bees, that can visit the flowers. Otherwise, you will need to perform hand pollination. Complete pollination is necessary for optimal fruit production.

Finally, avoid harvesting seeds from market-bought fruit, as many commercial cultivars are hybrids. Fruit grown from such seeds will not have the same characteristics as their parent plants.