Root Awakening: Periwinkle does not like wet feet

Periwinkle could be suffering from root issues

My Vinca plant was blooming. I watered it lightly every day and fertilised it with slow-release fertiliser monthly. Three weeks ago, the leaves started to yellow and curl downwards. Is this root rot and can I save the plant?

Sindy Ang

The Periwinkle plant’s roots will rot if they are kept wet for prolonged periods. Water may not evaporate quickly enough if you are using a moisture-retentive growing mix and if the plant is kept in the shade.

Give the plant direct sunlight and a well-draining growing mix. Let the root zone dry out slightly before watering each time. Stick your index finger into the growing mix to determine moisture levels. If it feels moist, watering can be withheld for that day.

If the plant has started to wilt, you may want to use the healthy portions for stem-cutting propagation.

Commercially produced Nerve plants are treated to maintain compact shape

My Fittonia used to grow in a terrarium. I propagated a cutting and now grow it indoors in a regular pot. Its leaves are huge. How do I get them back to normal?

Tina Lee

The changes in the plants can be attributed to the use of plant growth regulators that could have been applied to plants to keep them compact.

Treated plants will also develop smaller leaves. This practice is common in nurseries to obtain certain desirable aesthetic attributes in plants.

Once the effects of the chemicals have worn off, treated plants will revert to their usual growth habit. Such chemicals are not easily available and specific protocols need to be followed, which can be challenging for the average gardener.

Light levels can also affect the size of leaves. Under shadier conditions, plants can develop larger leaves to increase their photosynthetic capacity.

Save plants by taking stem cuttings

I left my Peperomia obtusifolia and Coleus Superfine Rainbow Volcano in the car for too long before transporting them home. I have tried adding water and putting them in the shade, but they have not recovered. How do I save them?

Lam Kwong Khiam

It appears that the two plants have dried out totally due to dehydration and heat stress. The roots may be dead and, if so, will not be able to take in water even if you irrigate them.

The only way to save the two plants is to see if you can find stems that are still alive, as can be seen in your Coleus plant. Cut the live stems and root them in growing media to start new plants.

Ensure Citrus has enough light and proper soil

My Citrus plant is not fruiting. Its leaves are falling and some are turning pale. The soil’s top layer is covered with algae. What is wrong?

Adrian Ling

Citrus plants require at least six hours of direct sunlight a day, as well as a friable, well-draining and aerated mix as the growing medium.

They do not thrive in heavy, compacted soil, which can retain too much water. The algae is an indication that the root zone is too wet.

You can prune the dead branches of your plant. Carefully remove it and replant it in more suitable soil. Your plant will likely suffer from transplant shock after the procedure, so keep it in a cool and shady site for it to recuperate.

Check aloe species to confirm it is safe to eat

How do I know if my aloe vera’s leaves are edible, and why are they longer and narrower than those sold in supermarkets? Also, why are the leaves growing downwards?

Valencia Lai

The older leaves of the aloe vera can be used to make desserts and other dishes once they develop sufficient leaf tissue.

The leaves of your plant are long and floppy due to a lack of light. Aloe vera needs a location with direct sunlight for at least six hours a day. Protect the plant from rain, as it will rot or develop leaf spot disease if the root zone is left wet during the rainy season.