How To Grow And Care For Ranunculus Flowers

Ranunculus are herbaceous perennials. They typically grow from corms (bulb-like structures). They grow up to 1 foot tall and produce lush, deeply lobed leaves that emerge from the ground in a rosette formation.

These plants flower in spring to early summer; flowers come in a wide array of colors. These flowers have cup-shaped multiple layers of petals that resemble roses. 

As they are perennials, Ranunculus can live for several years under the right conditions. The typical bloom of its beautiful flowers lasts for 4 to 6 weeks once they start producing flowers and cut flowers (kept in vase) can last an impressive 8 to 14 days. 

A Guide On Varieties

Some of the popular varieties of Ranunculus are described below:

• Persian Buttercup: This is the most common species grown in gardens. It produces large, double flowers in a wide range of colors including pink, red, orange, yellow, and white. The flowers are usually cup-shaped and appear in spring.
• Ranunculus Butterfly series: This variety includes Ranunculus that produce large, fully double blooms resembling peonies. The colors of this variety range from soft pastels to vibrant hues. They are widely used for cutting and floral arrangements.
• Tecolote: Tecolote variety is known for its exceptionally large and densely packed blooms. They come in bright colors and are widely in bouquets due to their long stems.
• Cloni: Cloni are hybrid varieties with ruffled petals and vibrant colors. They are favored by gardeners and florists for their unique and striking blooms.
• Elegance: Elegance variety is known for large, semi-double flowers. They come in soft pastel shades.
• Amandine: The Amandine variety of Ranunculus has large, fully double flowers similar to the Butterfly series. The ruffled petals present in them give a lush and voluminous appearance to the bloom.
• Ginette: Also known as the Hanoi Ranunculus, this popular variety is a favorite among brides. They have large, light-blush pink blooms and an abundance of petals. The stunning appearance and enormous size of Ginette make it perfect for bouquets and floral arrangements.

If you're looking to make the most out of Ranunculus in your garden, it is important that you provide the plant with certain planting requirements:

Climate: Ranunculus prefers temperatures that are not too hot (zones 7 or 8). They grow best in the places where the climate is cool to mild. They can also grow in warmer climates, but in such cases, they may benefit from partial shade during the hottest part of the day. It prevents the stress on the plants due to heat.

Humidity: Moderate humidity is best for the growth of Ranunculus. They can tolerate average humidity levels found in many regions but may benefit from slightly higher humidity during their growing season. Saying that it is also important to know that high levels of humidity can lead to fungal diseases in the plant if no proper air circulation is available.

Light: In cooler climates, full sun exposure is the best condition for the Ranunculus to bloom abundantly. In hotter regions, particularly during the peak summer, some afternoon shade can help protect the plants from excessive heat stress.

Soil: The best soil for the optimum growth of the Ranunculus plant is well-drained, fertile soil rich in organic matter. Sandy or loamy soils are the best soils for their cultivation. 

Corms are the main means of propagating the Ranunculus plants. In the prepared soil, corms are planted 2 to 3 inches deep making sure the "claws" or pointed ends are facing downwards. Immediately after planting, the corm-planted space is watered thoroughly.

If you are planning to plant multiple corms, it should be made sure they don't overcrowd. So, an individual space of 6 to 8 inches must be maintained to ensure each Ranunculus plant grows well.

Some other methods that are used to propagate them are from the division of corms or rhizomes from established Ranunculus, offsets or bulblets around the base of the main corm or seeds.

Ranunculus flowers bloom best when they are supplied with constant moisture. During their active growing phase,  water them continuously to prevent drying out of the soil. To decide whether it's time to water them, you can simply stick your fingers into the soil to make sure the top few inches are moist. 

For the dormant period, summer in the case of Ranunculus, reduce or totally stop watering them. The indication of dormancy is dried-out foliage. In this period, the corms rest which is then later implanted in the fall.

For Ranunculus grown in containers (plant in the ones with drainage holes for the best growth!), water thoroughly until water drains out of the bottom of the pot.

What To Avoid?

• Ranunculus should be watered at the base of the plant rather than overhead. This prevents the risk of fungal diseases that may appear due to wet foliage.
• It's better to avoid watering Ranunculus late in the day. This also prevents any fungal disease that prevails due to the presence of excess moisture in the soil.
• Don't water the Ranunculus at the same frequency on rainy days. Reduce overwatering during this time to prevent waterlogging.

A proper fertilization schedule needs to be established for abundant blooms. The fertilization should be started before planting Ranunculus. Adding well-rotted compost or organic matter into the soil is the best way to improve soil fertility and establishment of roots. 

A balanced fertilizer can be used during the plantation to provide initial nutrients to the growing Ranunculus plant. As the plant starts growing, apply a balanced fertilizer again. You may also switch to a nitrogen-rich fertilizer for growth enhancement of the vegetative parts. Later, as the plants start to bud, switching to potassium-rich fertilizers is necessary. 

The potassium-rich fertilizer encourages the flowering of Ranunculus. Continue to fertilize every 3-4 weeks with the same phosphorus-rich fertilizer to support continuous flowering. As the flowering stops and the foliage begins yellowing, you may fertilize one last time to help the plants store nutrients for the next growing season.

Additional Tips:

• The fertilizer should be applied around the roots of the Ranunculus plants. Be cautious that the fertilizer does not touch the foliage or flowers.
• Consider watering the plant immediately after the application of the fertilizer. This helps to solubilize the fertilizer and reach the roots successfully.
• Overfertilization does not mean better growth. Rather, it can lead to excessive foliage growth, or even burn the roots of the plants.

Pre-Plantation Care

Ranunculus corms are planted in the fall for varieties that bloom in spring. For varieties that bloom in summer, Ranunculus can be planted in early spring. The plantation site should have well-drained soil to prevent waterlogging which can cause the corms to rot.

Full sun is preferred for strong growth and full blooms of the plant.

Plantation Care

After planting the corms of the Ranunculus plants, make sure to water the plantation site to settle the soil around the corms. Plant the corms at the proper depth, and make sure the corms are not below 2  to 3 inches from the topsoil.

Doing so can delay the development of the plants. Also, to avoid overcrowding of the corms, a proper space of 6 to 8 inches is required, as this leads to competition for nutrients and moisture, resulting in smaller, less vigorous plants and fewer blooms.

Post-Plantation Care

Mulching: The Ranunculus plant loves moisture. So, to insulate the soil, the plant should be mulched with a layer of organic materials like wood chips, straw or compost. Mulches also help to suppress weeds and protect the corms from temperature fluctuations. 

Watering and Fertilization: Maintain regular watering during the growing season. The frequency of watering should be increased during dry spells. Make sure not to overwater as the Ranunculus plants do not tolerate waterlogged conditions. It is also recommended to highly focus on fertilizing during the active growth and flowering phase of Ranunculus. 

Deadheading: Towards the end of flowering, the Ranunculus plant begins the process of seed formation. So, to redirect this seed-forming energy, deadheading spent flowers is necessary. As a result, the plant focuses on forming new blooms. 

Post-Flowering Care: If you are planning to grow Ranunculus as a perennial, caring for the plant after the completion of the flowering phase is important. Once blooming is finished and foliage starts yellowing reduce watering and consider fertilizing one last time so the corms can store energy for the next growing season.

Ranunculus are less susceptible to diseases and pests and the chances of being infected get even rarer when the plant is grown in well-drained soil and gets full exposure to the sunlight. Some of the pests and diseases that are found associated with the Ranunculus plant are as follows:

1. Aphids

Aphids are small insects that hinder the growth of the Ranunculus plants. These insects are soft-bodied and can be green, black, brown, yellow, or pink. If they grow extensively, they form clusters on the undersides of leaves or around tender new growth.

They feed on the plant sap and show signs like leaves curling, yellowing and distorting. Their excretory secretion also have the tendency to attract other viral diseases. 

2. Thrips

Thrips are also insects that feed on the sap of plants. They mainly feed on the plant leaves causing their stippling or silvering. Thrips are also tiny and soft-bodied in structure. If the infestation gets severe, it affects the overall growth of the plant. 

3. Slugs

Slugs feed on leaves, stems, and flowers of ranunculus. They leave irregular holes or damage lower leaves and seedlings. They have a soft body and produce slimy substances wherever they go. 

4. Earwigs

Earwigs are insects that feed on flowers, young shoots, and foliage of the Ranunculus. They leave irregular holes in the parts they infest. Earwigs have elongated bodies.

The end of their abdomen possesses pincers or forceps. They are nocturnal; they get active at night and hide during the day.

5. Botrytis

Botrytis is a gray mold. These fungi are generally found in cool, humid conditions and produce grayish fungal growth on affected plant parts. If these fungi establish themselves, they can lead to the rotting of flowers and buds thereby reducing the ornamental value of the plant.

In the long term, the infected plant parts soften and collapse.

6. Blight

Blight disease is caused by both bacteria and fungi. This condition affects the stems and leaves of the Ranunculus plants, causing wilting, yellowing, and death of leaves and stems.

This condition arises under moist conditions and can readily spread to other plants. The infected plants gradually show lesions and ultimately die.

7. Pythium

Pythium causes root rot in plants. This can be a severe disease that directly causes the Ranunculus plants to die. Pythium thrives and spreads well in waterlogged and mainly on poorly drained soils.

The lower stems are also affected by the fungus. The symptoms of the infection show symptoms like yellowing, stunting, and eventual collapse of the plant.

Integrated pest management (IPM) practices can help effectively manage the disease and conditions related to Ranunculus plants. Keeping proper sanitation, taking care of the plants in the above-explained manner and crop rotation can be some of the practices for fruitful results.

The specific ways to manage the above-listed pests and diseases are mentioned below: 

1. The first step to managing the pests and diseases in Ranunculus is regular monitoring of the plants for the visible signs. 
2. For slugs, physical barriers like copper tape are available for slugs and sticky traps for thrips.
3. The slugs and earwigs can be manually removed by handpicking in the first phases of infestation. 
4. Introducing beneficial insects into the garden (like ladybugs) can help control the population of aphids and thrips biologically. 
5. Insecticidal soap, neem oil, or other organic pesticides can be used if the pests are highly increasing in number. 
6. For botrytis, overhead watering should be avoided as this can make the foliages susceptible to the infection. Also, the best time to water is morning, as any moisture on the plant will dry by evening. 
7. For blight also, managing moisture on the plants is important. Overwatering the plant should also be avoided to reduce conditions favorable for disease development.
8. As Pythium is a total root fungus, so if you have a history of previous infection in your garden by this fungi, it is best to rotate the Ranunculus plants to a new space. Consider planting ranunculus in raised beds or well-drained soil. Avoid overwatering to prevent the infection. 
9. As a last resort, fungicides and bactericides can be used for controlling the diseases caused by fungi and bacteria respectively.