My mother's friend gave her some stem cuttings of this plant (left). It has some soft thorns and is said to have medicinal properties. It took a while for the cuttings to grow and it has bloomed only once, producing orange flowers. What is this plant?

Dave Hong

It is a leafy cactus species that is called Pereskia bleo and commonly known as the Cactus Rose in English or "Seven Star Needle" in Chinese.

Its leaves are often eaten raw and believed to be used to treat various cancers and tumours, among myriad ailments.

Current scientific studies of its medicinal properties have been conducted only in the petri dish and cell lines. Hence, more in-depth work needs to be performed to ascertain the plant's efficacy in treating various illnesses in humans.

Lime plant not a cross-breed with hibiscus

I used to have hibiscus and Limau Purut plants, which had lobe- shaped leaves, but they have wilted. Now, I have this plant (left) growing out of the potted soil. When I shred its leaves, they smell like the Limau Purut, which is also known as Kaffir Lime. But its leaves are not lobe-shaped, though the stems have thorns like that of the Limau Purut. Could this plant be a variation of the Limau Purut or it could have been cross-bred with the hibiscus?

Anne Seow

The plant is not a Limau Purut (Citrus hystrix). From the description, it is a Citrus cultivar, likely a Four Seasons Lime (its botanical name is x Citrofortunella mitis) or a lime plant (its botanical name is Citrus aurantifolia) that was bought for display during Chinese New Year. It may also come as a grafted plant that has been grown on a lemon plant root stock, so do not be surprised new growth close to the base of the shrub has very different-looking leaves and other physical features.

The Citrus and Hibiscus genera are not closely related and are from two different plant families. It is not likely they have cross-bred.

If your plants are grown in containers, ensure they are large enough to support healthy plant growth. If the roots have filled the pots, you may want to move them to larger pots and fill the space with moisture-retentive potting mix.

Plants whose roots have filled their pots will not have sufficient nutrients for healthy growth and the limited soil volume cannot hold water for the plants to use.

During hot and dry weather, it is necessary to increase the frequency of watering to replenish water that is lost to the environment.

TIP: Grow small version of Ylang Ylang in small plots

The Ylang Ylang or Cananga odorata is best known for its fragrant essential oil that is used in aromatherapy and perfumery. It is said to be an ingredient in the classic perfume, Chanel No. 5.

However, it grows as a large tree and is not suitable for small garden areas. The good news is that there is a dwarf version of this plant, known botanically as Cananga odorata var. fruticosa.

This smaller version of the Ylang Ylang is suitable for growing in large pots or in the ground with well-draining soil in a small outdoor garden. It needs direct sunlight to grow well.

Climbing Fig's fruits are edible

I saw this plant (left) growing next to a bridge in my estate. Are the fruits edible figs? Can I propagate the plant or buy it from a nursery?

Stella Wong

The plant is commonly called the Creeping Fig or Climbing Fig. Botanically, it is known as Ficus pumila. It is a woody climbing fig species that grows on rough surfaces such as concrete and the bark of trees, via roots that are produced along the stem.

The plant needs to be exposed to full sunlight. When it grows large enough for its leaves and stems to overhang, a mature plant will produce fruits like those pictured. Its fruits have medicinal uses and are sometimes made into a dessert jelly.

The plant is easily propagated from stem cuttings and young plants can be bought from large nurseries. In the retail nursery, a cultivar with attractive variegated leaves is often sold in small pots as a house plant.

Lichen likely cause of spots

What are the grey spots on the stem of my grafted Michelia alba and are they harmful to the plant?

Tan Yu Jie

The grey spots are likely to be a type of lichen. It does no harm to the plant. However, remove the blue string around the stem. As the stem grows thicker, the string can girdle it and lead to the formation of a "weak zone" that will cause the stem to snap.

•Answers by Dr Wilson Wong, a certified practising horticulturist and founder of Green Culture Singapore (www.greenculturesg.com). He is also an NParks-certified park manager.

•Got a gardening query? E-mail it with clear pictures, if any, and your full name to stlife@sph.com.sg