Black Dahlia Care and Common Issues

Black Dahlia Flower
Black Dahlia (Source: Pinterest)

Dahlias are among the most attractive flowers that may be cultivated in our balconies and gardens. And black dahlia care is easy too!

They may appear overwhelming at first, but they are no more challenging to grow than regular roses or tulips in your yard.

Black Dahlia is an easy-to-care house plant that will give you abundant flowers with the appropriate care. Like every other flowering plant, they require plenty of light and just the right amount of hydration. Despite proper care, sometimes black dahlia is prone to a few diseases and pests.

 

Dahlia Blossoms
Dahlia Blossoms (Source: Gardenia.net)

Dahlias aren’t all the same. Some varieties may thrive in particular environments while others will perish.

You should know whether the plant requires full sun or can live in partial shade. For instance, some varieties of black dahlias require more water than others.

However, if you follow a few basic rules applicable for black dahlias, you will win them!

Let us now go ahead and find out the specific requirements of these black beauties, along with the common problems and their solutions.

Black Dahlia Overview

About a dozen Dahlias are designated as ‘black dahlias,’ as they all develop intense purple blooms that appear practically black based on the light setting.

The petals of multiple black dahlia cultivars can have a wide range of shapes.

The bloom size also differs considerably, ranging from 2-3 inches to over a foot across, and the deep hues of the blossom evoke a wide range of feelings among people.

Origin of the Plant

Black dahlias are native to Mexico, Colombia, and Central America. Because of the peculiar hollow stem, the Aztecs named the plant “Cocoxochitl,” which translates to “cane of water.”

Despite the extreme bitterness, the Dahlia was initially used to feed livestock on its leaves and shoots.

Around six Dahlia varieties have been cultivated as decorative plants, and they are prominent in the florist business and household yards across cities.

There are numerous variations of Dahlia hybrids, comprising single, double, pompon, cactus, waterlily, peony-flowered, and dinnerplate dahlias.

Zone Placement of Black Dahlia

You ought to figure out the hardiness zone of your location to get your black dahlias to look like that on Instagram and Pinterest.

And the most peculiar thing about the plant is, their care and adaptability are highly zone specific.

Zone 10 and Higher

Dahlias can be grown as perennials if you reside in zone 10 or higher, as winter safety is not required for the vegetation.

Zone 8 and 9

Soon after the first deadly chill in fall, expect the leaves to die back in response to changing temperature.

Make sure you securely trim the withered leaves 2 to 4 inches above the soil at this time.

Cover the soil with 4 inches of wood scraps, twigs, or other debris to shield the tubers.

Zone 7 and below

After winter has darkened the leaves, prune the Dahlia to a height of 2 to 4 inches.

Carefully extract clusters of tubers and scatter them out in a shaded spot. Wait a few days for the tubers to dry.

Fill a pot with damp soil, shavings, perlite, or vermiculite to preserve the tubers.

Position the pot in a cool, dry area with temperatures between 40 and 50 degrees Fahrenheit.

You can plant these tubers to get new plants for the upcoming spring.

Black Dahlia Care Tips

As beautiful and breath-taking as black dahlia appear, their care, on the other hand, is not so complicated as one might imagine.

I would not say they are fussy and attention-seeking. But like every other flowering house plant, they need a small amount of care and love.

However, the way your plant looks and the care tips might be heavily influenced by the season and location.

Below you will discover a few basic black dahlia flower care guidelines.

FactorCare Tips
Sunlight and LocationPlace in direct sunlight for at least 7 hours everyday.
Soil MixLight, healthy, and well-draining soil is best.
Watering ScheduleOnce or twice a week depending upon the plant size.
Fertilization RequirementFertilizers with an NPK value of 5-10-10 or 10-20-20 are ideal.
Pruning HabitsPruning the dahlias twice a year after the growing seasons promotes the health of the plant.
Toxicity of the PlantNon-toxic for humans but toxic for pets.
Temperature RequirementsTemperatures between 68°F and 72°F (20°C and 22°C) are ideal.
Humidity RequirementsBlack dahlias do best with a relative humidity of 75% - 85%.
Pest InfestationsHardwood ashes and diatomaceous earth are best to keep pests at bay.
Potential DiseasesAvoid overhead watering to eliminate the occurrence of diseases.

1. Sunlight and Location

Dahlias are absolute sun-lovers who require at least seven hours of direct sunshine every day. The more sunlight they receive, the fuller their blossoms will be.

So try to put your dahlias in the brightest spot possible.

2. Soil Mix

Light, healthy, well-drained soil is ideal for black dahlias. Several regular potting mixes fall into this category. Therefore any potting mix will suffice.

Note: Dahlias should not be grown in regions where the earth is wet or compressed.

3. Watering Schedule

The watering schedule for plants will vary according to the soil structure and seasonal changes. But Dahlias usually demand medium hydration.

Watering once a week or perhaps two times weekly, depending upon the size of the plant. And make sure to allow the topsoil to dry out before the next watering.

Watering Houseplants
Watering Houseplants (Source: Pexels)

4. Fertilization Requirement

You should fertilize black dahlias with a modest level of nitrogen. Fertilizers high in nitrogen might stifle blooms and injure the foundations.

It is best to use fertilizer occasionally and during the vegetative stage, from early spring to late summer.

Fertilizers with an NPK value of 5-10-10 or 10-20-20 are ideal for black dahlias.

However, try and avoid overfertilization and the accumulation of chemical salts in the potting mix.

5. Timely Pruning

Pinching is a technique for forcing plants to develop many shoots in which the apex of the top part is cut off.

Because each stem of the black dahlia typically only produces one flower, pinching is necessary if you want several blossoms. Once the plant has grown to a size of one foot, you can prune it.

As for potted dahlias, several prunes are frequently used to get more branches and create a dense appearance.

Dahlia will become huge if not pruned and will only offer a single bloom.

6. Toxicity of the Plant

Dahlia is not poisonous for human consumption. We can eat dahlia tubers, blossoms, stems, and even the entire plant for its licorice flavor.

Summer-growing dahlia tubers mimic fat potatoes in shape but not in taste.

Black dahlias, on the other hand, are edible for people but not for animals. The black dahlia flower poisons dogs, cats, and other animals.

If your pet ingests it, it may develop mild gastrointestinal and dermatitis symptoms.

While rubber plants may look aesthetically pleasing in your living room, they can be toxic to your pets. Learn more: Are Rubber Plants Toxic?

7. Temperature Requirements

Temperatures between 68 and 72 degrees Fahrenheit (20 and 22 degrees Celsius) are ideal for growing black dahlia.

The plant will also do good at a minimum night temperature of 60 to 64 degrees Fahrenheit (15 to 17 degrees Celsius).

Higher day or night temperatures will stimulate blossoms, but if the plant is maintained for long periods under these conditions, that’s not very helpful.

And, make sure you avoid temperatures above 80 degrees Fahrenheit (27 degrees Celsius) as black dahlias can get intolerant.

8. Humidity Requirements

If the humidity is very minimal, your dahlia tubers will become dehydrated and collapse.

And, on the other hand, you should worry about your dahlia tubers decaying or becoming moldy if the humidity is too intense.

Black dahlias do best with a relative humidity of 75 – 85 percent.

9. Pest Infestations

Slugs, snails, spider mites, thrips, and other vermin hide in dahlia pots. Hence, keep them free of twigs and other plant residues.

Conversely, if you detect gleaming snails and slug traces, keep soil height to no more than 2 inches.

Make sure to remove all weeds. You should remove the injured or broken plant parts carefully.

Slug
Slug (Source: Unsplash)

Hardwood ashes and diatomaceous earth, in some situations, produce abrasive obstacles that hinder slugs’ development and movement.

10. Potential Diseases

Fungi-caused dahlia diseases, including powdery mildew and gray mold, are among the most frequent illnesses in dahlia plants.

An excellent horticultural fungicide can help address almost all kinds of fungal diseases and keep your black dahlia at bay from diseases.

Additionally, make sure to avoid overhead watering.

Cruise through the table below to find out the diseases that affect black dahlias.

DiseaseSymptomsCare
Aster Yellows• Where flowers should be present, green and leafy tissue grows.
• The sections that resemble flowers are kept green or light green.
• Plants that have been affected should be destroyed.
• Leafhoppers must be controlled.
Bacterial Stem Rot• The core of blackened stems is soft and wet, with a terrible odor.• Dispose of diseased plants as soon as possible.
Gray Mold• Masses of gray spores grow on dark blotches on buds, leaves, or stems in moist conditions.• Keep the relative humidity low.
• To safeguard healthy plants, use a fungicide.
Powdery Mildew• A dry, whitish, mealy fungal growth appears on the upper surface of leaves.• Use a fungicide when the fungus is first noticed.
Storage Rot• Tubers decompose into a mushy, odorous mess.• Keep tubers in a cold and dry place.
• Before storing, allow the tuber surfaces to dry and remove any soil.
Verticillium Wilt• The plant wilts and dies, either as a single branch or as a whole.
• Affected stems have black, dark brown, or greenish-brown vascular tissue.
• Plant in a potting mix that is free of pathogens.
Virus• Visible rings and line patterns, or a mosaic of light and dark green are present on the leaves• Infected plants should be discarded.
• Tubers from infected plants should not be saved.
• Thrips must be controlled because they are the virus's vector.

11. Propagating the Plant

You will want more next year after savoring your blooming dahlias’ vivid colors and striking patterns.

You can propagate dahlias with seeds, tubers, or cuttings.

Pro Tip: It is wisest to propagate your black dahlias through tuber as they will produce baby dahlias precisely similar to the parent plant.

Hence, the following are the few ways to propagate your dahlias and multiply your collection effortlessly. Let’s check them out.

Tuber Division

The most frequent way to propagate dahlia tubers is to divide them.

Ensure that each section of the tuber has an eye before cutting it. If you can’t see the eyes, put the tubers in a small dish with moist cocopeat and wait for them to grow.

Sprouting the tubers before harvesting them has the drawback of making the sprouts fragile and easy to snap off.

Leave the tubers to dry for a week before planting them outside.

Stem Cutting

Stem cutting is one of the most popular methods of propagating black dahlias, especially if you see that the tubers have generated plenty of sprouts and you would prefer them to be planted in different pots.

Make sure the baby sprout is a few inches tall before removing it from the tuber.

While cutting the stem, remove a small plant of the tuber as well. A tuber is a growing point for the roots.

Coat the cutting in rooting hormone and place it in a container with clean water or plant them directly into a well-draining soil mix.

Seed Propagation

Seeds yield variants that are dissimilar to the parent plants. Thus, seed propagation is usually employed to create new cultivars.

Dahlia seeds planted between December to January or early spring will generate seedlings planted outside in late May.

A Sprouted Seedling
A Sprouted Seedling (Source: Unsplash)

Seed manufacturers supply a variety of bedding dahlias that develop quickly and are easy to propagate from seed. You can also plant the seeds preserved from your dahlia plants.

Steps to Propagate Black Dahlias with Seeds

To propagate a black dahlia from seed, follow the below pointed out steps.

  • Spread a container or seed tray halfway with damp soil and press the top gently.
  • Insert the dahlia seeds into the soil with care.
  • Cover the tray with an inflated clear polythene bag to maintain humidity.
  • In a few weeks, saplings will sprout. Plantlets are suitable to transfer into separate containers once the ‘real’ leaves have developed.
  • Carefully pluck seedlings out of the soil by holding them by their foliage.
  • And finally, carefully plant them.

Common Issues in Black Dahlia

Although black dahlias are pretty easy to grow and maintain, you might come across a few unhealthy circumstances making your plant look sad and floppy once in a while.

Below you will discover a few common issues in black dahlias and ways to address them wisely.

1. Wilting Plant

Lack of moisture is by far the most prevalent cause of wilting in black dahlias.

Dahlias, which are native to Mexico and Central America, require consistent watering to prosper.

As soon as your dahlias begin sending sprouts, keep the soil hydrated to a depth of 12 inches.

Maintain your dahlias in well-draining soil with a pH value of  6.5 – 7.0 so that your usual water routine doesn’t cause mushy situations.

Mulching around the plants helps keep good moisture levels and reduces weeds that battle for moisture with your dahlias.

2. Daytime Droop

Even though you keep the soil hydrated, you might see your dahlias wilting in summer.

Moisture is diverted from the stems and foliage to its bases, causing a limp outlook. This is the plant’s technique of defending itself during periods of crisis.

Your dahlias should brighten up as the sun sets and the day starts to cool. Screen your dahlias from the hot summer light to avoid drooping during the day.

3. Not Blooming

It could be as straightforward as lowering the sunlight and moisture demands of dahlias to induce them to flower. Dahlias prefer direct sun, which means at least six hours of bright sun per day.

A Budding Flower
A Budding Flower (Source: Pexels)

Even something slightly less implies that your dahlias will only yield a few blooms.

Your dahlias will most likely not flower if they are in partial or complete shade.

4. Yellowing Leaves

A few of the major causes of the dahlia leaves turning yellow is inadequate hydration.

Dahlia leaves turn yellow for a variety of reasons, one of which is an unbalanced soil pH. Dahlia leaves also become yellow due to stem rot.

Examine the plant for signs of stem rot and medicate as needed.

Points to Remember

We have gone through the black dahlia care tips, common issues, and others so far. And now we arrive at another critical segment of the article.

It is time for me to give you some pointers you must never forget as a black dahlia parent.

  • Place dahlia tubers in a cool but not freezing and high-humidity setting during the cold seasons.
  • Once the danger of frost has passed, transplant the tubers in full sun in a well-drained medium with plenty of organic materials.
  • After you have planted your dahlias, make sure not to overwater them. Until the seedlings are at least 6 inches to 12 inches tall, they require very little moisture.
  • You should stake dahlias as they mature to avoid falling over in the wind.
  • They will begin to produce blossoms around 12 – 16 weeks and continue until the first winter frost.
  • The most straightforward technique to keep dahlia blooms fresh longer in a vase is to keep them in freshwater.
  • After the plants have died back in the winter or autumn, pull up the dahlia tubers and preserve them for the following year.

Conclusion

Go ahead to the plant store and adorn your backyard with these exotic black beauties making a statement in the neighborhood.

And remember, your major trick to getting an entire plant with numerous black dahlia blooms is to place them in the sun and prune generously!

Have you got your first cute baby aloe vera plant and want to make sure you do everything correctly to help it grow healthy and beautiful? Learn how to take the best care of baby aloe vera plant.

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