Pentas lanceolata is the scientific name of pentas flowers. These warm-climate plants are upright perennial flowers that grow 3 to 4 feet tall and blossom year-round in tropical areas. The oval leaves and stems are covered with fine hairs. The tubular, star-shaped flowers reach 3 inches wide and bloom in white, pink, red and light purple colours. Pentas flowers attract hummingbirds and butterflies to the landscape.
Loosen well-draining soil in an area of full sun exposure to a depth of 12 inches with a shovel. Wait until late spring to plant the pentas flowers, so the new plants are exposed to the heat of the coming summer to increase their growth rates. Plant pentas flower bedding plants 15 inches apart in the ground. Space pentas closer together in a container.
Water pentas well by soaking the soil around the base of the plants. Allow the water to soak into the soil down to the root zone. Water only when there isn't any rainfall for five to seven days once the flowers are established and new growth appears.
Pinch new growth stem tips back to create a bushier, fuller plant. Take just the top 1-inch section of the tips off during the first month of growth. Pinching causes new branches to form along the stem. Pentas flower plants grow fine without pinching, but they look thin and scraggly with fewer branches.
Feed the pentas flowers every six weeks with slow-release 10-10-10 fertiliser. Sprinkle 1 tbsp around the root zone of the plant and scratch it into the top inch of soil with a hand cultivator. Water the fertilised soil immediately after applying to activate the fertiliser. Feed the plants only while they are actively growing during the spring and summer.
Take cuttings in the spring and summer from a strong, healthy pentas plant. Use a sterilised, sharp knife. Dip the 3- to 4-inch cutting into rooting hormone and plant in a small container filled with damp sand. Once roots form, transplant the new pentas bedding plants to their new locations.
Pentas flowers are low-maintenance flowers; their blossoms are located on terminal flower clusters and self-deadhead, which means they fall off naturally when they start to die.
Treat this perennial plant as an annual in areas with freezing temperatures. Pentas die in cold weather and have to be replanted the following spring. For winter survival, protect these flowers in a heated greenhouse.