Do you want to add a spiky, goth touch to your garden? Then the Black Narcissus is the dahlia variety for you. Tall, dark and handsome, this unusual plant produces dramatic flowers that will catch the eye of every passerby! If you have never taken care of a dahlia before, then no worries. This guide has all the tips to keep your black beauty healthy and attractive.
Table of Contents
Origins and Appearance
Nearly all dahlia species are native to Columbia, Mexico and Central America. While these plants were already known to indigenous peoples for generations, knowledge about them began to spread around the world once 16th-century Spanish botanists found the flowers growing in the hills of Mexico.
The Black Narcissus is a semi-cactus. It can grow to an imposing 39 to 40 inches (1 m) tall and produce flowers that are not truly black but they do come very close! The spiky flowers have a smokey red wine color, which is often darkly purple to the point of appearing black. This perennial bulb plant also has dark green leaves.
Temperature and Humidity
Your gorgeous new dahlia is a sun-worshiper. That’s right. You can plant this semi-cactus in that corner of your garden where there is full sun all day long (you know, that spot where nothing else survives!). A word of caution, though. Although this plant can weather the sun and most levels of humidity, it can be vulnerable to other conditions.
The Black Narcissus needs to be protected from frost, which is one of its main enemies. The plant also requires shelter from strong winds and flooding.
Watering and Feeding
When a Black Narcissus dahlia is planted in the ideal location (where there is full sun), the soil is going to dry out on a regular basis. In that regard, you are not looking at a water-saving plant. The dahlia needs frequent watering to prevent it from wilting or even perishing due to thirst.
This variety of dahlia is also a hungry plant. Once or twice a week, mix a good liquid fertilizer with water and pour the mixture onto the roots. You can also spray the fertilizer on the leaves for an extra “meal.”
A great liquid fertilizer is organic fish emulsion. This type of plant food can be diluted but no matter how often you use it, or how strong you make the dilution, the emulsion will never burn your plants. Fish emulsion is perfect for heavy feeders like dahlias.
Soil and Repotting
Remember when we said that your dahlia is constantly craving food? You will get great results if you also prepare the soil beforehand to satisfy this need. Before you plant the bulbs, work organic matter into the flower bed to make the soil humus-rich and tasty!
The soil also needs to be well-draining. Since frequent watering is a key factor in this dahlia’s care, you also run the risk of water-related problems like root rot and fungal infections. The best prevention is to make sure that the moisture does not overstay its welcome. Aim for loamy, sandy soil that does not hold onto water.
You can indeed grow this tall dahlia in a container. This is perfect if your home is located in an area where there is frost. When the latter is around the corner, you can bring your plant indoors or move it to another safe location. Since this variety draws heavily on nutrients, you need to repot it a few times a year. But if you plant it in rich soil and give fertilizer on a regular basis, repotting can be limited to 2 or 3 times a year.
Get all the best tips on how to re-pot your house plants.
When to Prune a Black Narcissus Dahlia
During the flowering season, deadheading will encourage your plant to produce more of its iconic flowers. But once this period is over and autumn arrives, cut the plant to ground level and extract the tubers. The latter can be stored over winter and planted again in spring.
Pests and Diseases
This dahlia variety has several pests and problems. As tragic as that sounds, the truth is that the plant is actually quite hardy. However, you need to know which issues can arise with this flower so that you can treat them as soon as possible.
Below, we cover the most common insects that love to take a bite out of dahlias. You can treat all of them with a good organic horticultural soap or pesticide. You can also avoid outbreaks by giving your plants enough room for air circulation, correct watering, and preventive applications of pesticides.
Most gardeners have seen these green bugs. They appear in groups, often along the stems or underside of leaves. They also attack new growth, so keep an eye out to make sure that any new leaves are not on the menu.
Spider mites are arachnids that leave web-like structures on the plant. Signs of a heavy infestation include yellow or brown leaves that appear sickly.
These shell-less gastropods also appear on dahlias. Use an organic product to deter slugs and snails alike.
There are plenty of natural ways to deter caterpillars from munching on your dahlia’s leaves. Here are 10 ways to stop caterpillars from eating your plants.
The flies are not the real pest, per se. But their larvae will eat your plant’s leaves with gusto. The main sign that the larvae are already there is the unsightly discolored (often white) lines and patches on the leaves.
Diseases and Problems
More often than not, you can grow Black Narcissus dahlias and not experience any diseases during the plant’s entire life cycle. However, let’s look at the most common problems so that you are prepared when the symptoms appear.
When this fungal infection pops up, the main symptom is a layer of gray dust on the leaves (this is the spores of the mold). The bad news is that plants can infect each other with this rapid disease. This is another reason why your dahlia plants need to be spaced well apart or kept in pots. Another useful tip is to keep the humidity under control. Gray mold spores can only germinate when humidity is 93 percent or above.
If your plant is infected, use a high-quality organic fungicide and apply as per the product’s directions.
Powdery mildew is similar to gray mold in the sense that it is a fungal infection and leaves light-colored spores all over the plant. The difference is that powdery mildew appears in clusters that resemble spots, often on leaves, stems, and even flowers.
This variety’s germination process responds well to warm soil. Plant the bulbs during the warmer days of spring for the best results.
All dahlia species are considered to be toxic. If you have young kids or pets that like to chew on plants, you can consider safer flowering plants. But should your heart be set on a Black Narcissus, simply pot the plant and place the container out of reach.
Yes, you can cultivate your own dahlia at home. This variety can be propagated through softwood cuttings as well as tuber division. You can also store the tubers at the end of autumn and plant them in the spring.
This lovely plant can be an annual or perennial. It depends on the gardener. Some people leave their dahlias to grow by themselves for 2 or even 3 years. But the best dahlias are grown from fresh cuttings or tubers every year.
The Black Narcissus dahlia is not difficult when it comes to soil pH. It will happily grow in soil that is alkaline, acid or neutral.
Boost the chances of successful propagation by taking cuttings from late winter to early spring. These cuttings are best taken from plants kept in a greenhouse as most garden dahlias are either already pruned for winter or resting.