Rudbeckia maxima — a medium houseplant, prefers full sun light
SPECIMEN · FROM THE LIBRARY
Rudbeckia maxima

Rudbeckia Maxima

Updated · 81 observations
ON THIS PLANT

Rudbeckia maxima, commonly known as the giant coneflower or cabbage leaf coneflower, is a perennial plant native to the central and southern regions of the United States. A member of the Asteraceae family, it can grow up to 8 feet tall with a spread of 3 to 4 feet. The plant features large basal leaves that can reach up to 2 feet in length and have a blue-green color with a waxy texture.

The flowers of Rudbeckia maxima are yellow-orange with dark brown centers that resemble cones. These blooms appear from mid-summer through early fall, attracting bees, butterflies, and other pollinators.

This plant thrives in full sun or partial shade and prefers well-drained soil. While it is drought-tolerant once established, it benefits from regular watering during dry spells. Additionally, Rudbeckia maxima is deer-resistant.

Often used as an ornamental plant in gardens, Rudbeckia maxima is appreciated for its impressive size, attractive foliage, and showy flowers. It also makes an excellent cut flower for floral arrangements due to its long stems.

Overall, Rudbeckia maxima is a stunning addition to any garden or landscape, providing beauty throughout much of the growing season while requiring minimal maintenance once established.

A note from PlantMom

Great Coneflower is fairly disease-resistant and generally not prone to illnesses. However, it can be vulnerable to pests and diseases present in its environment. These problems are typically not severe. In terms of care, this plant needs moderate maintenance. It should be pruned regularly to keep a neat appearance and encourage healthy growth. Fertilizing can also help stimulate flowering. Great Coneflower is suitable for anyone with outdoor space, such as a garden or patio, and does not require extensive care experience. It may need more attention when grown indoors.

— PlantMom
CARE GUIDE

How to keep Rudbeckia Maxima.

Light

Great Coneflower grows best when it receives light for most of the day. It also does well in locations where light is present for part of the day. Uneven light exposure can cause reduced growth, lower plant vigor, and fewer blooms.

Water

The Great Coneflower thrives in moist, well-drained environments, preferring consistent moisture but showing some tolerance to drought. To maintain optimal soil balance, watering once a week is ideal. This plant is best suited for outdoor growth, where it can benefit from natural rainfall. It is important to keep the soil evenly damp without allowing it to become waterlogged.

Temperature

Great Coneflower is native to climates with temperatures varying from 41 to 95 °F (5 to 35 °C). It does best within this temperature range. As seasons change, small adjustments to temperature may be helpful to mimic its natural habitat.

Fertilizer

The best time to fertilize a Great Coneflower is in early spring, when it is coming out of dormancy and starting active growth. Fertilization supplies essential nutrients for healthy growth. Although Great Coneflower has relatively low fertilizer requirements, an annual application can improve its survival and encourage better, longer-lasting flowers.

Pruning

The Great Coneflower boasts tall stems and vibrant yellow blooms. To maintain its health and appearance, prune in early spring to remove any damaged stems, and again in late spring to tidy up spent flowers, which encourages growth and flowering. Be sure to clean your tools to prevent the spread of disease. Regular pruning also improves airflow and sunlight exposure, which benefits this sun-loving plant.

CHARACTERISTICS

Botanical profile.

Plant Type
Herb
Life Cycle
Perennial
Genus
Rudbeckia
Family
Asteraceae
Hardiness Zone
5-9
Mature Height
1.52 m to 2.13 m
Mature Spread
0.91 m to 1.22 m
Leaf Color
Blue, Green, Gray, Silver
Leaf Type
Deciduous
Flower Color
Gold
Flower Size
2.54 cm to 7.62 cm
Bloom Time
Early summer, Mid summer
Planting Time
Spring
Harvest Time
Mid summer
ALSO KNOWN AS

Other names.

en Cabbage coneflower en Great coneflower en Giant coneflower en Cabbage leaf coneflower en Large coneflower
FREQUENTLY ASKED

Reader questions.

How should I water my Great Coneflower?

When watering the Great Coneflower, it is important to use filtered water that is at room temperature. Tap water may have harmful particles, so filtered water is preferred. The plant comes from a warm environment, so it is best to avoid using cold water as it may shock the plant. Additionally, overhead watering should be avoided to prevent foliage complications. Instead, water the plant by applying filtered room temperature water directly to the soil until it is fully soaked. This helps to moisten the roots and promote their growth and nutrient absorption.

Why should I put fertilizer on my Great Coneflower?

Fertilization is important for the Great Coneflower and other plants because it provides essential nutrients for growth. Although the Great Coneflower has relatively low fertilization needs and can survive without it, annual fertilization can greatly benefit the plant, promoting its survival and improving flower quality. Those who want their Great Coneflower to look its best should prioritize annual fertilization.

What are the sun requirements for Great Coneflower?

The Great Coneflower requires full sun, characterized by more than 6 hours of sunlight a day, or partial sun, which means about 3-6 hours of sunlight daily. It's crucial to observe how sunlight moves through your garden to select locations that ensure an optimal balance of light and shade, contributing to the well-being of your plants.

What are the ideal temperature conditions for growing Great Coneflower?

Great Coneflower thrives in climates where the temperature ranges from 41 to 95 °F (5 to 35 °C). It has a strong resistance to cold, making it adaptable to various thermal conditions. Slight adjustments in temperature with the change of seasons can be beneficial to mimic the natural habitat of the Great Coneflower. During winter, special frost protection measures are generally not needed, but in cases where temperatures are expected to drop below -25°C, it's important to provide protection by covering the plant with soil or straw. Moreover, watering the plant abundantly before the first freeze in autumn is recommended to ensure the soil remains moist and enters a frozen state, which helps prevent drought and water scarcity for the plant during the colder months.

What should I do if I give my Great Coneflower plant too much water or not enough water?

Overwatering and underwatering can harm your Great Coneflower, but overwatering is more commonly seen. When the plant gets too much water, the stems and leaves may wilt and turn yellow. Overwatering for a long time can also cause root rot, mold, and mildew, which can kill the plant. Underwatering is less likely, as the Great Coneflower tolerates drought well. However, it is still possible, and in such cases, the leaves become brittle and brown. It is important to recognize signs of overwatering early on. Some diseases caused by overwatering, like root rot, may be irreparable if not addressed promptly. Reduce watering immediately if you notice these signs and check the soil quality. If the soil drains poorly, replace it with a loose, well-draining potting mix. Conversely, if signs point to insufficient water, increase watering until the signs disappear.

When should I fertilize my Great Coneflower for the best results?

The best time to fertilize a Great Coneflower is during late winter to early spring when it is transitioning from its dormant phase to active growth. Fertilizing at this time promotes healthy growth and helps the plant kickstart the season. Although early spring is the most beneficial, fertilizing during the fall is also acceptable. However, it is not recommended to feed a Great Coneflower during summer or winter.

What are the essentials for growing Great Coneflower successfully?

For optimal growth, the Great Coneflower needs substantial light exposure throughout most of the day but can also thrive with light available for a part of the day. Insufficient light exposure may result in less vigorous growth and reduced blooming. In conditions where natural light is inadequate, artificial lighting can be a suitable alternative, especially during winter or in less sunny spaces. LED lights are recommended for indoor plants, with full sun plants requiring 30-50W/sq ft, partial sun plants needing 20-30W/sq ft, and full shade plants requiring 10-20W/sq ft of artificial light. The light should be placed 12-36 inches above the plant and provided for 8-12 hours a day to mimic natural sunlight conditions.

How does low temperature affect Great Coneflower and what solutions are recommended?

Great Coneflower is cold-tolerant and performs best when temperatures are kept above 5°C. In the winter, it should not be exposed to temperatures below -20°C. When temperatures fall below -25°C, the plant may not show immediate damage but could have decreased or no sprouting in the spring. In such cases, any parts of the plant that have failed to sprout should be removed in the spring as a part of its care routine.

How much water does my Great Coneflower need?

If your Great Coneflower is in a pot, the most precise way to determine if it needs water is to check the soil by sticking your finger into it. If the top two to three inches of soil are dry, it is time to water. If you have the Great Coneflower planted outdoors, you can use the same method. If the top few inches of soil are dry, it is time to water. During the spring and early fall, you will likely need to water this plant about once a week using this method. However, in extremely hot weather, you may need to water it at least twice a week or even more. It is important to note that a mature and well-established Great Coneflower has the ability to withstand drought conditions.

When is it better to not put fertilizer on my Great Coneflower?

To ensure optimal growth of your Great Coneflower, it's best to fertilize it only during late winter and early spring. This plant has low fertilizer needs, so a single annual feeding is enough. Fertilizing during spring, summer, and fall can lead to overfertilization and its associated issues. However, if you missed fertilizing in spring, it's okay to feed it in the fall. It's important to note that you should refrain from fertilizing during most of the growing season and also during winter. During the winter, the Great Coneflower is in a dormant phase and does not produce new growth, making fertilization unnecessary.

What are the symptoms of light deficiency in Great Coneflower?

Symptoms of light deficiency in Great Coneflower include smaller new leaves, leggy or sparse growth, increased leaf dropping, halted growth, lighter-colored new leaves, and chlorosis or loss of leaf green color. Excessive sunlight can cause sunscald, leaf curling, wilting, and leaf scorching, indicating damage to the plant's tissues and affecting its health.

What should be done if Great Coneflower is exposed to high temperatures?

During the summer, it's crucial to ensure the Great Coneflower is not exposed to temperatures above 35°C. Exposure to temperatures exceeding 38°C can cause the leaves to lighten in color, become prone to curling, suffer from sunburn, and in severe cases, lead to wilting and drying of the entire plant. To mitigate these risks, affected parts should be trimmed away. The plant should also be moved to a location that provides shade during the midday and afternoon sun or protected with a shade cloth. Additionally, watering the plant in the morning and evening to maintain soil moisture is recommended to help the Great Coneflower cope with high temperatures.

PLATES
Rudbeckia maxima leaf
PLATE 01 · leaf
Rudbeckia maxima leaf
PLATE 02 · leaf
Rudbeckia maxima flower
PLATE 03 · flower
Rudbeckia maxima flower
PLATE 04 · flower
Rudbeckia maxima habit
PLATE 05 · habit
Rudbeckia maxima habit
PLATE 06 · habit
ALSO IN THE LIBRARY

You might also like.