Root Awakening: Grafted plants may produce dissimilar leaves

Growth with dissimilar leaves the result of rootstock

Why have the kaffir lime leaves in this new branch changed to look like lime leaves?

Esther Leong

Kaffir lime (Citrus hystrix) is often grafted onto another Citrus species serving as a rootstock as stem-cuttings are difficult to root on their own. Common rootstock plants include lime and lemon.

From the photograph, the new growth with leaves that are dissimilar to those of the kaffir lime are likely to have arisen from the rootstock. You can prune the branch at the base.

Epiphyllum needs optimal growing conditions

Why are the leaves of this plant turning yellow? How can I make them green again and bloom more often? There are hardly any flowers now.

Chong Yuen Foong

The yellowing of leaves of your Epiphyllum plant could be due to a number of reasons. Do you fertilise your plant regularly? The generalised yellowing could be due to a lack of nitrogen.

Also, ensure the growing media is well-draining and not soggy. A wet root zone will prevent the development of a healthy root system and uptake of nutrients. This cactus grows as an epiphyte and should be potted in a porous growing media.

This plant may benefit from being grown in a location with filtered sunlight. Intense direct sunlight can cause the leaves to turn yellow, especially if the plant is also allowed to dry out.

Water plant well during hot weather

Why are the leaves of my lemon plant curled up?

Fong Yoke Chan Teresa

The curling of leaves in a plant could be due to a lack of water. Does this happen during the heat of the day? Check if the growing media below the surface is moist. During hot and dry weather, the plant can lose water excessively, and it will wilt and leaves will go limp.

Ensure that you water your plant deeply early in the day so that the root zone is hydrated. You may need to water again later in the day if the growing media has dried out.

You may want to move the plant into a slightly larger container if the roots have filled the current pot. A larger volume of growing media can hold more moisture for the plant.

During repotting, check the health of the roots – healthy roots should be firm and white. An unhealthy root system will prevent the plant from taking up water from the growing media.

Move Philodendron to a brighter location

I bought two Philodendron billietiae about 15 months ago and planted them at this site. The left side of the location has less sunlight than the right because of the shade from the surrounding trees. Both plants seemed to grow well until about six months ago. The plant on the right looks healthier than when it arrived, with more leaves, but the plant on the left is down to one full green leaf. Why is this so and should I place the plant on the left elsewhere?

Amos Chan

Philodendron does not thrive in deep shade. In general, plants fare better if they are grown under filtered sunlight for four to six hours daily. As such, you may want to transplant the less healthy plant to a location that is brighter for better growth. You may want to prune the overhead branches to allow sufficient light exposure for your plants below the tree.

Plant choices are dependent on the green wall system

I have an outdoor green wall that gets direct full sunlight. Other than money plants, what other plants are suitable for the site?

Peng Chung Cheow

Money plants do better in areas with filtered sunlight. Under full sunlight, their leaves can burn.

To get better advice on the choice of plants, it is vital to know the type of green wall system in your garden.

Assuming the system is one that has multiple containers that house growing media, note that these containers are small and hence the growing media in them tends to dry out fast. Small containers will limit how big plants will grow.

If the location has direct sunlight for more than six hours daily and, depending on the container size, you can consider drought-tolerant flowering plants such as the Moss-rose purslane (Portulaca grandiflora), Thornless Euphorbia (Euphorbia geroldii), Lantana (Lantana camara) and Madagascar Periwinkle (Catharanthus roseus).

To grow these plants well, ensure the growing media is well-draining. The watering schedule should be such that the growing media gets a chance to dry out slightly before being irrigated again.