Pentas Will Add Low-Maintenance, Star-Shaped Blooms to Your Garden—How to Grow Them

Pentas, also commonly known as Egyptian Star Clusters, are tropical plants that do best in warm, humid climates. In these growing conditions, this perennial plant will thrive year after year but in climates colder than USDA Zone 10, it’s grown as an annual.

Pentas grow between 1 and 3 feet tall and have a mounded growth habit with dense foliage, characterized by narrow, tapered green leaves. The star of the show during the growing season is the plant’s tubular flowers, which grow in clusters with each individual blossom featuring five petals in a distinct star shape.

Pentas are a great choice for a pollinator garden because the nectar-rich flowers attract hummingbirds, butterflies, and bees.

Pentas Care

These are the primary care requirements for growing pentas.

• Plant in a well-draining soil.

• Choose a location that receives at least six hours of sunlight for the best blooming.

• Water during periods of dry weather but don’t oversaturate the soil.

• Fertilize on a monthly basis during the growing season.

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Planting

To add pentas to your landscaping, plant them in the spring. Dig a hole for each plant that is about 12 inches deep and spaced 12 to 24 inches apart to allow room for each plant to fill out.

Pentas can also be grown in containers. They look particularly good when several plants are grouped together in a large container or pot. You’ll need to consistently water pentas grown in a pot but they look stunning when the cluster is in bloom.

Light

Pentas prefer full sun conditions but can be grown in partial shade. However, if these plants receive less than six hours of light each day, expect reduced flowering activity.

Soil

A range of soil conditions are suitable for growing pentas but these plants prefer rich, well-draining soil. A neutral pH level is ideal but pentas will grow in slightly acidic or slightly alkaline conditions. If your soil pH is too acidic, add dolomitic lime to raise the pH level closer to neutral (a pH of 7).

Water

When first planted, water pentas regularly. Once the plant is well-established, rainfall is typically sufficient to meet the plant’s moisture needs and the plant exhibits moderate drought-resistance. However, during extended periods of dry weather, water pentas plants.

When watering pentas, be sure to water from the base of the plant rather than overhead. Excess water on the foliage can cause fungus, especially in the hot, humid climates where pentas thrive.

Temperature and Humidity

Pentas are tropical plants that prefer hot temperatures and high levels of humidity. These plants are hardy in USDA Zones 10-11.

Fertilizer

To support foliage production and flowering activity, you can fertilize pentas during the growing season using a well-balanced fertilizer, like 5-5-5. Apply a liquid fertilizer formula every four to six weeks during the spring and summer.

Types of Pentas

• ‘New Look Red’: Growing to a height of about 24 inches, ‘New Look Red’ features bright red flowers with a white center, adorning your garden from spring to early fall.

• ‘Starcluster White’: This pentas variety grows to about 24 inches and produces white flowers that stand in contrast to the plant’s abundant green foliage. It has a branching growth habit that makes it easy to snip flower clusters for bouquets or vase arrangements.

• ‘Dwarf White’: A more compact variety of pentas, this plant reaches 12 to 15 inches at maturity. Dwarf varieties in other colors can be found as well, including red and violet.

• ‘Graffiti Violet’: Another pentas variety that stays small is ‘Graffiti Violet’. It also reaches a maximum height of about 12 inches and is known for its prolific light purple blooms.

How to Get Pentas to Bloom

Pentas are best known for their star-shaped flowers and vigorously bloom throughout the growing season. Each pentas plant produces up to 20 flower clusters, known as corymbs.

Bloom Months

Pentas typically bloom in the spring and summer months. In many climates, it’s possible for pentas to bloom until the first frost, making these plants a long-lasting choice for the flower garden. In USDA Zones 10 and 11, pentas will grow as a perennial and bloom year-round.

What Do Pentas Flowers Look and Smell Like?

This plant is characterized by its tiny flowers, available in attractive shades like red, pink, white, lavender, and yellow to complement your landscaping. Pollinators are drawn to the flowers but there is no detectable fragrance from the plant while it's in bloom.

How to Encourage More Blooms

Other than deadheading spent flowers, pentas don’t need much encouragement to blossom. But if you notice reduced flower production, it may be that the plant is receiving too little light.

For pentas grown in a container, move the plant to a location that receives at least six hours of sun each day. You may need to transplant pentas that are planted in a garden location with insufficient sunlight.

Insufficient nutrients can also stifle flower production. Amend the soil with compost or apply a balanced fertilizer formula during the growing season to raise the level of nutrients available to the plant.

Common Problems With Pentas

One reason that pentas are so popular is their low-maintenance care requirements. There are relatively few pests and diseases to watch out for and the plants are considered to be somewhat drought-tolerant. Still, imbalances in regards to light or water can cause problems for pentas.

Leaves Turning Yellow

If the leaves of a pentas plant begin to turn yellow, it’s likely to be a sign of overwatering. Although this plant does well with consistent soil moisture, the soil should freely drain to prevent soggy conditions that can lead to root rot.

A case of root rot will first affect the health of the plant’s root ball but as it progresses, yellowing foliage is an indicator of trouble below the soil’s surface. To try and remedy the situation, forgo any supplemental watering for the plant. It may be necessary to dig up the plant and trim away any affected roots. Amend the soil to improve drainage before replanting.

Another reason that plant leaves turn yellow is nutrient deficiency. Pentas prefer soil with a neutral pH but also tolerate slightly acidic soil. However, if the soil is too alkaline, then iron solubility is adversely affected and the plant may not be able to absorb sufficient levels of this nutrient. Take steps to make your soil more acidic.

Drooping Leaves

If the normally perky green leaves of a pentas plant begin to droop, it may be a sign of overwatering. It can also be an indicator of fusarium wilt, especially if the lower leaves are the first to show this symptom.

In the case of fusarium wilt, expect to see wilting during the day, with the plant seemingly making a recovery at night. There is no recovery for plants affected by this bacteria and it’s best to remove the plant and destroy it to prevent the disease from spreading.

Frequently Asked Questions

Do pentas come back every year?

Pentas are a perennial plant that will return every year in USDA Zones 10 and above. However, in colder growing zones, this plant is grown as annual and will die back when temperatures dip below freezing.

Do pentas like sun or shade?

Pentas prefer full sun growing conditions but they can be grown in partial shade. If you plant them in partial shade, flower production will be reduced.

Do pentas grow better in pots or in the ground?

Although pentas are frequently planted in garden beds or borders, they’re also suitable for growing in pots. As long as you choose a container that is large enough and you keep up with regular watering and fertilization, pentas can thrive as flowering container plants.

Do pentas spread out?

Pentas will spread as they reach maturity, spanning 2 to 3 feet in width. How much the plant spreads is generally in proportion to its height; more compact varieties reaching just 12 to 18 inches in height will have a smaller spread to match. In their native habitat in Africa or Yemen, pentas are known to grow much taller—these plants can reach a mature size of 6 feet tall with a 6-foot spread.

Read the original article on The Spruce.