Has the Gothic gardener living inside of you always yearned for very dark roses? It seems impossible to get a completely black rose, let alone a living rose, but don't give up right away. With the right method, you can change the color of rose petals – whether they are live flowers or cut flowers – to be as dark as the night sky.
Method 1 of 3: Planting Dark-Colored Roses
Step 1. Choose a dark rose variety
Although breeders and genetic engineers have tried to make roses black, no rose is considered 100% black. Choose dark rose varieties. Although breeders and genetic engineers have tried to make roses black, no rose is considered 100% black. However, you can grow flowers that are very dark, with a slight red or burgundy hue, using proper cultivation techniques. Start with rose varieties that produce dark flowers with velvety textured petals. Ask a florist for advice, or try looking for one of the following varieties:
- Black Jade is one of the most popular dark roses, but it is prone to pests and diseases. Roses will darken in hot weather.
- Black Baccar a may be among the easiest roses to get, but unfortunately the flowers are small and unscented. Roses appear darker in cold weather.
- Midnight Blue is one of the darkest purple roses you can get. The flowers have an unusual clove scent.
- Other options include Nigrette, Black Magic, Black Pearl, Black Ice, Black Beauty, Blackout and Taboo. Before buying roses, you should seek information about the required climatic conditions and sizes.
Step 2. Grow roses in a greenhouse if possible
Factors such as temperature and light can affect the color of the roses that will be produced. For best results, grow roses in a greenhouse so you can control these factors accurately.
- Don't forget to look for information about rose varieties or you can ask the nurse at the nursery about the space requirements, soil type, and the level of sun exposure needed.
- In general, you need soil with good drainage ability to plant roses. Soil pH should be slightly acidic or neutral.
- Dig a hole slightly wider than the root base, and about the same depth. For rosebushes, holes are usually 40-45 cm deep and 45-60 cm wide. After inserting the plant and filling the hole with soil, add mulch and fertilizer about 2.5-5 cm.
Step 3. Consider watering the roses with flower dye
Some online sources suggest adding black food coloring to the water that will be used for watering plants. This method may not be effective because the roots will not absorb most of the dye. If you want to try it, you should first consult with the florist what flower coloring professionals usually use. This dye is usually intended for cut flowers, not live flowers, but will likely not harm the rose tree.
Step 4. Wait for the buds to start growing
As flower buds begin to appear, the plant continues to focus its energy on growing the flower stem. As soon as the stems stop growing and the buds start to sprout, it means the plant has reached a critical stage of development. About 90% of the pigment that determines flower color is created after the bud has reached of its size, but has not yet bloomed.
If you have a rose variety that blooms several times a season, keep a record of bud development on a calendar and use it to track flower development for the next period. The final stage of flower bud growth will usually last about 2 weeks before the flowers bloom
Step 5. Experiment with the temperature at which the buds get bigger
During this stage, the temperature can drastically affect the color. Most varieties of roses have not been studied in this way. So you will be a pioneer. If possible, try different techniques for different types of buds or the same group of buds. Here are some guidelines you can use to get started with your experiment:
- Cold temperatures usually increase the amount of pigment produced so the flowers will usually have a darker color. A study of Crimson Glory roses produced purplish roses at 23ºC, and darker red roses at 13ºC. These experiments tend to be more successful in hot weather.
- Heat stress will cause flowers to wilt or produce a more orange color, but there are some exceptions. For example, Baccara's roses may turn blue at the end of the experiment. This technique is risky because it can cause flowers or plants to die. If possible, ask the florist for help to determine a temperature that can suppress the plant without killing it. A study of Jaguar roses (in orange) exposed their buds for 3 days at 39ºC during the day and 18ºC at night.
Step 6. Experiment with light
During bud development, keep the Baccara rose in the shade for a darker blue. Other varieties may need sunlight to get color. If in doubt, try to shade some of the rose branches, but leave the rest out in the sun.
Step 7. Protect the blooming flowers from the sun
The darker the color of the flower, the more sunlight it will absorb. After the live flowers bloom, place them in partial shade. Or, you can cut the flower and try the following method to make the color darker.
Some roses will bloom a deep red in cooler weather and tend to turn black during hotter weather. If the resulting flower color isn't what you expected, you may need to take the risk of exposing it to the sun
Step 8. Prune your rosebush
Pruning will keep your roses healthy as it helps encourage the growth of new shoots and flowers, removes dead branches, and improves air circulation. You can prune your roses around March (when the weather is cooler), or depending on the variety you are growing.
- Use a clean, sharp tool every time you do your pruning. Remove any dead, broken, diseased, or wilted stems and twigs that are weak, or smaller than a pencil stem. Do not forget to get rid of saplings that grow at the base of the plant.
- After that, you need to prune the healthy stems while keeping in mind that new branches will emerge from the buds. Prune from the bottom of the plant and make cuts at a 45-degree angle, about 0.5 cm above the shoot that is facing the outside of the plant.
Method 2 of 3: Darkening the Color of Cut Roses
Step 1. Start with a dark cut rose
This method explains how to preserve dark roses, and encourage roses to turn almost black in color. The varieties of roses mentioned above can be good choices.
- Flowers that are in half bloom may stay dark and last longer than roses that are in full bloom.
- If you can't find dark roses at the flower shop, choose roses with velvety petals. This texture will make the rose look darker.
Step 2. Try soaking the flowers in water or preservatives (optional)
If the flower color is dark, continue with the next step. If the color is lighter than expected, you can try soaking it in water for a few days. The resulting effect is usually small and may be difficult to predict, but this method usually causes the flowers to turn bluer and darker. In general, water causes a darker effect than flower preservatives, although results may vary depending on the variety. If you have a large supply of flowers, try this method for each flower type in a separate vase.
- You can buy flower preservatives at flower shops and nurseries. A home solution of mixing acid and sugar can produce a similar effect.
- For more tips on preserving roses, you can read this article.
Step 3. Dry the flowers upside down
Whether you store flowers in liquid or not, drying flowers often results in a darker color. Hang the flowers upside down in a warm, dry place out of the sun. You should wait about 2 weeks or so before the flowers are completely dry.
Step 4. Spray flowers with floral preservative spray (optional)
Once the flowers are dry, you can spray them with flower spray so the roses will last longer. Spray on dried roses following the directions on the package.
Don't try to clean the flower first as this could damage the petals
Method 3 of 3: Coloring Cut Roses Black
Step 1. Choose a rose
Usually, white roses or light colored roses are the best choices. These roses have very few colors so they are easier to turn into the color you want. When staining, it's hard to detect if you're using dark roses.
- If you cut the roses yourself, use sterilized branch shears. Using regular shears will damage the stems so they can't absorb water and dye.
- Cut the roses at a 45-degree angle to create a wider surface for water and dye absorption.
Step 2. Select the colors to use
Although some people have tried mixing black food coloring in water, professional flower dyes are safer for flowers. You can buy them online, or ask a florist to order them for you.
Step 3. Remove the cut flowers from the water
Wait at least three hours after cutting roses or bringing them from the flower shop. Stressed flowers will absorb more water, and that means more dye.
Step 4. Mix warm water and dye
Check the label on the package for the recommended concentration. If you're not sure, mix 1 tablespoon of flower dye with 1 liter of warm water. The water should not be too hot, or approx. 38 °C. Mix the ingredients properly in a heat-resistant container large enough to hold the roses.
Add flower preservatives to make flowers last longer
Step 5. Put the roses in the water, while maintaining the water temperature
Roses have thick woody stems that can take several hours (or even a full day) to change color. To avoid uneven and imperfect coloring, try to keep the water temperature around 38ºC. For that, you can add warm water from time to time or place the entire container in a slow cooker set at that temperature.
Step 6. Lift the rose
Once the rose turns black, remove the flower. Rinse off the dye stuck to the stems and transfer the flowers into a vase filled with plain water.
If the color of the flowers is uneven, leave them in warm water without dye overnight to allow the color to spread evenly
- Contact some botanists and gardeners at local colleges for further assistance. Usually they are happy to give advice.
- You can also buy flower paint to dye flowers. This method doesn't change the natural color of the petals, but it can be the quickest solution.
- Don't try to stain with paint or fabric dye, as this will kill the roses.
- Be careful if planting roses in direct sunlight. The heat absorbed by dark colors can overheat roses.