Kailan may need bigger pot to grow

I transplanted a kailan seedling to a cut-up plastic bottle measuring about 9cm in diameter and 15cm in height. Is there enough space for it to thrive? Are there other tips for growing this plant?

Alan Tok

The soil volume you have provided for a single kailan or Chinese kale plant looks to be just sufficient for it to grow to a size that can be harvested for consumption. You will need a bigger pot if you want your plant to grow larger.

Like most leafy greens, it needs at least six hours of direct sunlight a day, and regular applications of organic fertiliser rich in nitrogen and iron. You may need to cover it in a netted enclosure to deter pests such as caterpillars, snails and slugs.

Plant may be dehydrated, suffering from fertiliser burn

My Brazilian Spinach’s leaves have turned yellow at the edges. I have placed the plant in a corridor and water it daily. How can I keep it healthy?

Helen Han

Do you fertilise your plant regularly? Also, if the growing area is windy, it can dry the plant out.

The burnt leaf edges could be due to damage from excessive fertiliser application or drying fertiliser salts in the root zone. Soluble salts from fertiliser can draw out moisture, causing the plant to wilt and the leaves to turn yellow. Keep your plant moist and hydrated at all times.

However, the damage is purely aesthetic and the remaining leaves are still safe to consume. Prune the plant regularly to ensure the production of new and tender leaves.

The brown edges could also be due to fungal infection, so the plant needs to be grown in a site with sufficient sunlight as well as air circulation. This ensures that the leaves do not remain wet for too long.

Murraya needs direct sunlight

I have had a Murraya plant for almost two years. When I bought it, it flowered once, but did not do so again even after I applied fertiliser. It also wilts after rain due to its thin stem. How can I help my plant grow healthy and strong?

Wong Chee Hoong

Without a picture, it can be difficult to ascertain the health of the plant. In general, the Murraya, most commonly known as the Orange Jessamine, has to be grown under full sun for best results. A lack of light can cause it to become thin and spindly, and it will not flower under such conditions. In Singapore, this plant blooms only seasonally.

If the plant is growing in the shade, move it to a sunny spot. You may need to prune it selectively to reduce the weight of its crown. Stake the plant to provide additional support. With regular pruning, the stem should thicken over time.

Frangipani bears fruit in pairs

A new pod has grown from the stem of this frangipani tree. What is it?

Ann Chan

The brown pods are the fruit of the frangipani, which are borne in pairs. The fruit will mature and eventually split open to disperse its seeds. If you want to save the seeds, use plastic netting to make a “bag” to cover the fruit. You can collect the seeds from within the bag and replant them.

Buddhist pine may have died due to transplant failure

We have had this tree for almost three months and the leaves have been turning brown since last week. Some car shampoo had seeped into the soil, so we raised the concrete nearby. Our tree supplier says the problem could be chemical burn or a lack of water. How can we save it?

Peter Lim

Did your Buddhist Pine turn brown after you tried to move it by raising the concrete? From the picture, it appears that the tree has been trenched, but the resulting root ball is too small.

Depending on the species, larger and more sensitive trees need to be trenched progressively over a period of time before they can be moved. Aftercare is very important to ensure the survival of the tree.

If a root ball that is too small is taken and if aftercare is not done properly, a transplanted tree can die. From the picture, your plant may already be dead. Check if there are live branches, which will still be pliable when bent. Dry, dead branches snap instantly. Even if the tree is still alive, it may no longer look pleasing.

In general, do not cover the collar of a tree by raising the soil profile. This can cause the base of the trunk to become wet, which can in turn lead to disease.

• Answers by Dr Wilson Wong, an NParks-certified practising horticulturist, parks manager and ISA-certified arborist. He is the founder of Green Culture Singapore and an adjunct assistant professor (Food Science & Technology) at the National University of Singapore.
• Have a gardening query? E-mail it with clear, high-resolution pictures of at least 1MB, if any, and your full name to stlife@sph.com.sg. We reserve the right to edit and reject questions.