Few cacti express the transition from winter to the growing season as clearly as Notocactus warasii, now generally classified as Parodia warasii. For much of the year, it is an elegant green, strongly ribbed cactus with fine spines and a calm architectural presence. Then, after a proper winter rest and the return of stronger light and warmth, large silky yellow flowers appear near the crown.

The flowers are so bright that they seem to bring their own sunlight. This is the thought behind the title: once the flowers open, the sun comes out.

Parodia warasii is native to southern Brazil and is admired by cactus collectors for its fresh green body, pronounced vertical ribs, relatively gentle spination and dependable flowering when cultivated in accordance with its seasonal rhythm. At TOMs FLOWer CLUB, the offered specimen is not a single cactus but a naturally composed family of five to six established plants of different sizes growing together in one pot. As the plants mature, the arrangement continues to change and develop.

A Brazilian Cactus with a Surprisingly Green Appearance

Parodia warasii belongs to the family Cactaceae and originates from the southern Brazilian state of Rio Grande do Sul. It was historically known as Notocactus warasii, and the older name remains deeply established among cactus growers and collectors.

Modern botanical classifications generally place it in the genus Parodia, which includes numerous South American cacti formerly treated under genera such as Notocactus, Eriocactus and Wigginsia. The change in name reflects botanical research rather than a change in the plant itself. For many collectors, both names remain useful:

Accepted name: Parodia warasii
Traditional horticultural name: Notocactus warasii

The plant's bright green colour can surprise people who associate cacti with grey, blue or heavily spined desert plants. Its green epidermis reflects an active photosynthetic body adapted to a climate that is not simply hot and dry throughout the year.

Southern Brazil has seasonal rainfall, changing temperatures and periods of cooler weather. Parodia warasii is therefore not a cactus that should be treated as though it came from an extremely dry desert. It needs excellent drainage, but it also benefits from regular watering during active growth.

This distinction is important. Good drainage does not mean permanent drought.

The Architectural Character of Parodia warasii

A mature Parodia warasii is immediately recognisable by its:

• Fresh green, globular to short-columnar body
• Strong, well-defined vertical ribs
• Fine, pale yellow to brownish spines
• Symmetrical growth
• Large, glossy yellow flowers produced near the crown
• Long-lived habit when grown with a healthy root system

Young plants are generally rounded. With age, they become more elongated and may develop into substantial columnar specimens.

The ribs are not merely decorative. They allow the cactus body to expand after absorbing water and contract gradually during dry periods. This flexible structure helps the plant manage changes in water availability without damaging its epidermis.

The fine spines provide some protection from herbivores and can also influence the amount of sunlight and airflow reaching the plant's surface. Their comparatively delicate appearance gives P. warasii a softer visual character than many heavily armed cacti.

Why the Flowers Appear After Winter

One of the most rewarding characteristics of Parodia warasii is its flowering behaviour.

The plant usually produces its large yellow flowers during the warmer, brighter part of the year, often after experiencing a cooler and drier winter rest. The winter period is not simply a pause imposed by growers. It reflects the seasonal rhythm to which many South American cacti are adapted.

During winter, lower temperatures and shorter days reduce metabolic activity. The cactus uses less water, and growth slows substantially. If it is kept warm, wet and heavily fertilised throughout winter, it may continue growing weakly, but this can interfere with the natural rhythm that supports compact growth and flowering.

A proper winter rest helps the plant conserve energy and prepare for the next growing season.

When light levels increase and temperatures rise in spring, the cactus resumes active growth. Flower buds may then develop near the crown.

This is why a cactus that appears unchanged throughout winter can suddenly become one of the most colourful plants in a collection.

“Once Flowering, the Sun Comes Out”

The flowers of Parodia warasii are large in proportion to the cactus body. Their petals are usually a clear, luminous yellow with a silky sheen, while the centre contains numerous yellow stamens surrounding the stigma.

The flowers open in response to favourable light and warmth. On bright days, they may open widely and display their full colour. During cool, dark or overcast conditions, they may remain partly closed.

This behaviour is not a fault. Flower opening is connected to the plant's reproductive biology. Opening under warm, bright conditions can improve the visibility and accessibility of the flower to pollinating insects.

For a grower, this creates a familiar experience: the flower buds appear, but the display may only reveal itself fully when the weather becomes bright.

Then, almost suddenly, the cactus looks as though it has captured the sun.

A Cactus Family Rather Than a Single Plant

The specimen offered by TOMs FLOWer CLUB consists of five to six established Parodia warasii plants of different sizes growing together in one pot.

This creates a more natural and dynamic composition than a single isolated cactus. The different heights and ages give the planting depth, while the repeated ribbed forms create visual harmony.

Over time, each plant continues to develop at its own pace. The arrangement therefore changes gradually rather than remaining static.

A multi-plant composition also offers an interesting view of the species' development. Smaller plants show the compact juvenile form, while older plants reveal the more mature structure.

When several plants flower at similar times, the effect can be particularly striking.

How to Grow Parodia warasii Successfully

Light: the more light, the stronger the plant

Parodia warasii prefers a very bright to sunny position.

A south-facing window, bright conservatory or sunny balcony can be suitable. Strong light encourages compact growth, healthy spine development and flowering.

Plants grown in insufficient light may become elongated or lose their balanced shape. This is called etiolation. Once a cactus has stretched, the affected growth does not become compact again, so adequate light is important from the beginning.

When moving a plant from an indoor location to strong outdoor sun, acclimatise it gradually. Sudden exposure to intense sunlight can cause sunburn, particularly after a dark winter.

Water: generous during growth, restrained during rest

During spring and summer, water thoroughly when the substrate has dried sufficiently.

The exact interval depends on temperature, light, pot size and airflow. A cactus growing in warm, bright conditions may use water much more quickly than one kept indoors during a cool period.

Avoid watering according to a fixed calendar. Check the substrate instead.

During winter, reduce watering substantially. A cool, dry winter rest is generally preferable to a warm, wet winter.

Substrate: drainage protects the roots

The substrate should be very permeable and fast-draining.

A suitable cactus mixture should contain a significant mineral component, such as pumice, lava, coarse grit or other stable inorganic materials. The organic component should provide some moisture and nutrients without remaining wet for prolonged periods.

The purpose is not simply to make water disappear quickly. A well-structured substrate also creates air spaces around the roots.

Roots require oxygen. In a dense, permanently wet substrate, oxygen becomes limited and root damage can follow.

Temperature: warm in summer, cool and dry in winter

During active growth, Parodia warasii appreciates warmth.

For winter, a cooler, bright and dry environment is beneficial. The exact temperature depends on the plant's condition and the growing environment, but the plant should be protected from frost.

Although the species originates from a region with seasonal variation, it should not be regarded as reliably frost-hardy in cultivation.

Fertiliser: moderate nutrition is enough

Use a balanced cactus fertiliser during active growth, but avoid excessive feeding.

A cactus does not need to be pushed into rapid growth. Too much fertiliser can produce softer tissue and may encourage growth that is less compact.

Moderate feeding supports healthy development without disturbing the plant's natural rhythm.

Repotting: only when necessary

Repot during the active growing season when the root system has filled the pot, the substrate has deteriorated or the plant requires more space.

Do not repot immediately before winter. The roots need time to recover and establish themselves before the cooler resting period.

For the offered multi-plant arrangement, repotting should be approached carefully. The composition has been created to allow the plants to grow together, and there is no need to separate them unless a future change in presentation is desired.

The Most Common Cultivation Mistakes

Overwatering in winter

This is one of the most serious risks.

During winter, the plant uses little water. Wet substrate combined with cool temperatures can damage the roots and increase the risk of rot.

Insufficient light

A cactus may survive in a dark room, but it will not develop its best form or flowering potential.

A dense, water-retentive substrate

Ordinary houseplant compost often retains too much moisture. Cactus roots need a substrate with both drainage and air.

Excessive fertilisation

Rapid growth is not necessarily healthy growth. A compact, slowly developed cactus is generally stronger and more attractive over the long term.

Expecting flowers from a young plant

Flowering requires maturity. A healthy young cactus may need time before it is capable of producing flowers.

Collector Insight: Why This Species Remains Special

Parodia warasii is not rare because it is difficult to grow. It is appreciated because it combines several qualities unusually well.

The plant has a strong geometric form without aggressive spination. It remains attractive throughout the year and then produces large yellow flowers that completely change its appearance.

Experienced growers also value its response to seasonal cultivation. It rewards attention to light, watering and winter rest without requiring complicated techniques.

The key is to understand the plant rather than simply follow a care schedule.

At TOMs FLOWer CLUB, the cacti are cultivated with emphasis on strong roots, natural growth and long-term health. They are not treated as short-lived decorative objects. A well-grown cactus can remain part of a collection for decades.

Frequently Asked Questions

Is Notocactus warasii the same plant as Parodia warasii?

Yes. Notocactus warasii is the traditional name still widely used in horticulture, while Parodia warasii is the currently accepted botanical name in many modern classifications.

How often does Parodia warasii flower?

A mature, healthy plant may flower regularly during the warmer growing season, especially after a suitable winter rest. Flowering frequency depends on age, light, health and cultivation conditions.

Does Parodia warasii need full sun?

It prefers very bright light and benefits from direct sun. However, plants should be acclimatised gradually to intense outdoor sunlight to prevent sunburn.

How should I water it?

Water thoroughly during active growth, then allow the substrate to dry appropriately before watering again. Keep the plant much drier during winter.

Is Parodia warasii frost-hardy?

No. It should be protected from frost. A cool, dry winter rest is beneficial, but freezing temperatures can cause serious damage.

Is it suitable for beginners?

Yes. It is a relatively straightforward cactus when provided with strong light, excellent drainage and careful winter watering.