Giant Coreopsis (Coreopsis gigantea)

Also known as: Giant Coreopsis

The plant you're referring to is Giant Coreopsis (Coreopsis gigantea). This woody, succulent perennial is native to coastal areas of western North America and is often grown by nurseries. It thrives in drought conditions but is vulnerable to frost. As a member of the sunflower family, it produces bright yellow flowers during the spring and summer and can reach heights of up to 1.2 meters.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting

Attributes of Giant Coreopsis

Lifespan

Perennial

Plant Type

Herb

Plant Height

91 cm to 1.8 m

Spread

60 cm

Leaf Color

Green

Flower Size

5 cm to 8 cm

Flower Color

Yellow Blue

Images of Giant Coreopsis

Quickly Identify Giant Coreopsis

Thick, woody trunk reaching 3-6 feet (91-183 cm) provides strong structural support.

Stout gray-brown stem, 2-4 inches (5-10 cm) thick, stands out prominently.

Bright green, deeply lobed pinnatifid leaves emerge in winter, distinctive foliage.

Large showy yellow daisy-like flowers, 3 inches (7.6 cm) across, bloom late winter to late spring.

Sculptural stems post-foliage adds unique visual interest in the landscape.

Scientific Classification of Giant Coreopsis

Phylum

Vascular plants

Class

Dicotyledons

Order

Asterales

Family

Daisy

Genus

Calliopsis

Species

Giant Coreopsis

Planting and Growing of Giant Coreopsis

Care Difficulty

Easy

Watering Schedule

Every 3 days

Sunlight Requirements

Full sun

Sunshine Duration

6-10 hours

Ideal Temperature

60-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Giant Coreopsis?

For Coreopsis gigantea, aim for about 250 milliliters of water per session. This type of plant thrives when the soil is allowed to partially dry out between waterings. Make sure the top inch of the soil is dry before the next watering. This prevents the roots from sitting in water, which can lead to rot.

What are the symptoms of an underwatered Giant Coreopsis? ›

What should I do if my Giant Coreopsis is not getting enough water? ›

What are the symptoms of an overwatered Giant Coreopsis? ›

How to save an overwatered Giant Coreopsis? ›

What Are the Sunlight Requirements for Giant Coreopsis?

Sunlight Requirements: Full sun

Duration of light: 6 to 8 hours

Coreopsis gigantea requires full-day sunlight exposure, benefiting from 6 to 8 hours of direct sunlight. This light range ensures strong growth, abundant blooms, and bright flower colors.

How much sun does Coreopsis gigantea need? ›

What solutions help achieve this lighting? ›

What are the benefits of ideal lighting conditions? ›

More About Sunlight Requirements Techniques→

What Is the Ideal Temperature Range for Giant Coreopsis?

Ideal Temperature: 60 ~ 75℉

The ideal temperature range for Coreopsis gigantea is between 60°F and 75°F. This range supports the plant's natural growth cycle, promoting healthy blooming and minimizing stress. Temperatures in this range typically mimic the plant's native coastal habitat, where it thrives along Californian shores. Maintaining these conditions helps optimize photosynthesis and metabolic processes, ensuring vibrant displays during the flowering season.

What Soil is Best for Giant Coreopsis?

Soil type: Sandy soil, Loam

Soil PH: 6.5 ~ 7.5

Coreopsis gigantea thrives in well-draining soil to prevent root rot. Ensuring that the soil does not retain excessive moisture enhances plant health by protecting delicate root systems. Though not highly demanding, Coreopsis gigantea benefits from nutrient-rich soils, which contribute to robust growth and an abundance of vibrant flowers. Fertility helps sustain foliage and flowering cycles. The preference for sandy soil helps Coreopsis gigantea roots penetrate easily, promoting strong and vigorous growth. This texture allows roots to explore and access available nutrients efficiently.

How to Fertilize Giant Coreopsis?

Fertilizer type: Balanced

For Coreopsis gigantea, an appropriate amount of fertilizer ensures sustained growth and vibrant blooms. When using liquid fertilizers, it's advisable to dilute the product according to the manufacturer's instructions, usually at a concentration of 1 tablespoon per gallon of water. Slow-release fertilizers can be applied more sparingly, typically around 1 tablespoon spread evenly over the root zone. This prevents nutrient burn while supporting healthy development.

How to Prune Giant Coreopsis?

Pruning Time: Spring, Summer

Start by identifying any dead or diseased branches—which can be found by their brownish, dry appearance—and remove them first. This helps the plant direct energy towards healthier parts. Trim back the longer, leggy branches to create a balanced shape, maintaining the plant's natural, bushy appearance. Aim for an even, well-rounded canopy for the best aesthetic results. Make cuts at a 45-degree angle about 1/4 inch above a leaf node or bud. This encourages healthier growth and helps protect the cut area from water retention and disease. More About Pruning Techniques→

How to Propagate Giant Coreopsis plant?

Propagate Time: Spring,Late spring

Select a healthy stem with several nodes and use sharp pruners to cut a 4-6 inch segment. Remove the leaves from the bottom half to prevent decay in the soil.

Fill seed trays with a well-draining potting mix and gently press the seeds into the surface. Cover them lightly with soil and water thoroughly. Maintain consistent moisture until germination.

Dip the cut end of the cutting in rooting hormone and plant it in a pot filled with a mix of perlite and peat moss. Water it well and cover with a plastic bag to retain humidity.

More About Propagating Techniques→

How to Repot Giant Coreopsis plant?

Repotting frequency: Every 2-3 years

Coreopsis gigantea signals it's time for repotting when you observe roots emerging from drainage holes or a noticeable decrease in growth rate. These signs, often paired with a lack of flowering, indicate that the roots need more space to expand. Spring and autumn are ideal seasons as the plant is less stress-prone.

Select a pot that is slightly larger than the current one, ideally 1-2 inches in diameter bigger. Opt for pots with good drainage holes to prevent water from stagnating. A well-chosen pot helps balance moisture, encourages healthy root growth, and supports the plant's top-heavy structure.

Choose a well-draining sandy soil mix, rich in nutrients but loose enough to allow water to flow freely. This type of soil prevents the roots from sitting in water, reducing the risk of rot and mimicking the plant's natural coastal habitat, ensuring healthy growth and vibrant blooms.