Root Awakening: Monstera’s yellow spots may be result of injury

Monstera’s leaves are diseased

My monstera’s leaves have been turning brown and dying. What is wrong with it? It gets filtered sunlight in the morning at the balcony and is watered every evening.

Han Tong Guan

The yellow spots may be caused by fungal or bacterial disease. Such infections may come about as a result of injury to the plant, such as improper handling or change of growing conditions.

Prune the infected leaves to reduce the likelihood of the disease spreading. Ensure your plant gets enough air circulation and appropriate levels of light, especially if it is moved from a shady location to a sunnier one.

Depending on the growing conditions, make sure its growing mix drains properly and that the root zone is not perpetually wet. Adjust your watering frequency so the root zone can dry out slightly before you water it again.

Split stems will lead to a structurally weak tree

How do I save the split branches of my frangipani?

Tan Chuen Yen

The wound resulting from the split branches will not heal properly, which can lead to infection and other issues in the affected area. It is best to prune the branches.

Monitor the growth of your tree’s branches and make sure they do not become too bulky and heavy, as these can break amid heavy rain and strong winds. As your tree grows, prune it progressively to maintain proper form and stability.

It may help to install a support system to keep the tree stable and prevent tree failure. When in doubt, you can engage a certified arborist from a landscape company for advice.

Bonsai infested with sap-sucking insects

My bonsai appears to have been infested with a fungus-like substance which is spreading to other plants. How do I save it?

Tjai Mee Kien

It is not clear from the picture what is affecting your bonsai, but it seems as though sap-sucking pests may be the culprit.

You can use a strong jet of water to wash them off your plant, but make sure it is not so strong that it damages your bonsai. Wash the plant thoroughly to make sure all parts are pest-free.

Inspect your plant daily for pests and take action immediately if required.

Prune plant to manage its size

My plant has been growing taller and its flowers are blooming. Can I prune it once the flowers have bloomed?

Helen Lim

Your plant is the variegated version of the Willow-leaved Justicia (botanical name: Justicia gendarussa), which can get lanky as it grows.

The flowering portion can be cut down to the semi-hardwood portion of the plant, so that it can produce new branches that will eventually lead to a bushier growth habit with further pruning. However, avoid pruning too low down the shrub, as older parts of the plant may not regrow.

Plants must be grown in better conditions

I am having issues with my four plants. Plant A’s leaves are turning yellow. Plant B’s leaves are drying up at the same time that new ones are sprouting. Upon repotting, I saw its roots were clumped together and not growing properly. Plant C sprouted many flower buds that fell before blooming, while Plant D seems to be stunted. What should I do?

Julia Queck Kim Choo

For the Flaming Katy (Plant A; botanical name: Kalanchoe blossfeldiana), the yellow leaves could be due to a wet root zone that is preventing the plant from taking up nutrients.

As it is a succulent plant, grow it in well-draining, gritty media and in a sunny spot. Give it slow-release fertiliser pellets for proper nutrition. The current growing mix of coconut husk chunks may retain too much water and will break down over time.

Plant B could be a cultivar of Rhodendron, a festive flowering plant popular during Chinese New Year. Its leaves could be browning due to transplant shock brought about by root disturbance, pest infestation or hot weather. 

Opening up the tangled root system may have led to transplant shock and damaged roots. A damaged root system will be unable to take up water for the plant and some leaves will turn yellow. Place the plant in a cool but bright location to recuperate before gradually moving it back to its original spot.

For the desert rose (Plant C), do not overwater the plant as this can lead to the abortion of flower buds. Ensure that the buds have not been damaged by heavy rain, especially if the plant is exposed to the elements. Pests such as thrips can also damage flower buds and cause them to fall.

For the rosemary plant (Plant D), place it in a location that gets at least six hours of direct sunlight a day and make sure it is in a well-draining growing mix that is allowed to dry out slightly between watering sessions. Feed the plant with a weak solution of water-soluble fertiliser or a few pellets of slow-release fertiliser to promote growth.