Plant Parenting: Colour-changing flowers in your garden to delight the senses

SINGAPORE – Flowering plants are popular additions to any garden, as they inject colour and beauty into a landscape.

But colour is only one part of their charm. The sweet scent of these blooms not only delights the senses, but also attracts pollinators.

Few sights in nature are as captivating as flowers that change colour with age. These changes occur at different rates, but it is not unusual to see flowers with different colours in a single inflorescence.

The transformation can be attributed to changes in the chemical structures of their floral pigment compounds, enzyme activities, pH levels, successful pollination or a combination of these factors.

These changing colours play a key role in plant reproduction. The hue of a new bloom signals to pollinators that the flower is fresh and full of nectar. Once pollination has occurred or the flower begins to age, the fading colour acts as a visual cue that the flower is no longer fertile or rewarding – so pollinators can focus elsewhere.

Here are six flowering plants that thrive in the tropics. Grow them outdoors so they get plenty of direct sunlight, and keep them in well-draining soil.

Yesterday, Today and Tomorrow (Brunfelsia pauciflora)

This perennial plant can be shaped to grow as a shrub, or allowed to grow into a small tree of about 1.5 to 2m tall.

With regular fertilisation, it can produce many fragrant flowers that turn from purple to blue or mauve, and finally to white, over just a few days – hence its name.

Japanese Honeysuckle (Lonicera japonica)

This perennial woody vine produces scented flowers that start out white and turn yellow before they fade. Its common name in Chinese translates to “Gold and Silver Flower”.

You can train it to grow onto a vertical support as a climber, or use it as a sprawling ground cover.

Its fresh flowers can be picked and dried. They are used in traditional Chinese medicine to make a tea that is said to have anti-inflammatory properties.

Rangoon Creeper (Combretum indicum)

The Rangoon Creeper is a large perennial vine that needs to grow on a strong support. Once established, it is relatively drought-tolerant.

Its fragrant flowers grow in a hanging cluster and are white when newly opened. The upper surface of each flower turns pink and then red with age.

The flowers are edible, and can add a splash of colour and sweetness to salads.

Golden Gardenia (Gardenia mutabilis)

The Golden Gardenia produces blossoms quite unlike the common white ones that most gardeners may be familiar with.

Its flowers start off creamy white before turning yellow and finally orange. It has a long floral tube that opens in the evening and emits a strong scent to attract moths, which are its natural pollinators.

The Golden Gardenia grows as a lanky shrub with arching branches and glossy leaves.

Dwarf Ylang-Ylang Tree (Cananga odorata var. fruticosa)

As its common name suggests, this is the dwarf version of the Ylang-Ylang tree. It grows to about 2m tall and can be planted in a row to form a hedge.

Its flowers smell similar to those of its larger counterpart, the essential oils of which are often used in perfumery.

The flowers have a unique, octopus-like appearance with curled petals. The young flowers are green when they first appear and turn yellow as they mature. The intensity and quality of the floral scent also changes as the flower ages.

River Tarenna (Tarenna fragrans)

River Tarenna is a native, free-flowering tree often seen in local parks, gardens and streets. It is a small low-branching tree that grows up to 2.5m tall.

The flowers are sweet-smelling and rich in nectar, which attracts pollinators, and grow in a dense cluster. They are white when they open and turn yellow over time.

Under the right conditions, the flowers will bloom all year.