Black Jade is one of the most popular dark roses, but can be vulnerable to pests and disease. [2] X Research source It turns dark in hot weather. Black Baccara is likely the darkest commonly available rose, but the flowers are small and unscented. It appears darker in cooler weather. Midnight Blue is one of the darkest purple roses available. It has an unusual clove scent. Other options include Nigrette, Black Magic, Black Pearl, Black Ice, Black Beauty, Blackout, and Taboo. Before buying any rose, check climate requirements and size.

Always look up your variety or ask a garden nursery for information on space requirements, soil type, and sun levels. In general, when planting your roses you’ll want a soil with good drainage. The soil pH should also be slightly acidic to neutral. [3] X Research source Dig a hole that is slightly wider than the plant’s root ball, but about as deep. For a rose bush, this will typically be about 15 to 18 inches (38 to 46 cm) deep and 18 to 24 inches (45. 7 to 61. 0 cm) wide. Then, when you’ve placed the plant and filled in the hole, add 1 to 2 inches (2. 5 to 5. 1 cm) of mulch and fertilizer.

If you have a rose variety that blooms multiple times a season, note the bud development on a calendar and use it to track the development of the next round of flowers. This final stage of bud growth will usually take place about two weeks before the flower opens. [5] X Research source

Cool temperatures tend to increase the amount of pigment produced, which usually means darker flowers. One study of Crimson Glory roses produced purplish roses at 73ºF (23ºC), and darker, redder roses at 50ºF (13ºC). [6] X Research source This is more likely to work in summer. [7] X Research source Heat stress usually leads to faded or more orange flowers, but there are exceptions. For example, Baccara roses may end up deepening to a bluer shade. [8] X Research source This is a risky technique that can cause flower or plant death; if possible, ask a florist to help you choose temperatures that will stress the plant without killing it. One study of (orange-colored) Jaguar roses exposed buds to three days of 102ºF (39ºC) daytime / 64ºF (18ºC) nighttime temperatures. [9] X Research source

Some roses will bloom dark red in spring and fade to black during summer. [12] X Research source If you’re unsatisfied with the appearance of your roses, you may want to risk exposing them to sunlight.

Always use clean and sharp tools. Remove all dead, broken, diseased, or dying canes as well as weak or twiggy branches that are thinner than a pencil. Also remove any suckers from the plant. Then, you’ll want to prune the healthy canes – keeping in mind that new branches sprout from the eye buds. Prune from the bottom of the plant up and make your cuts at a 45 degree angle, about ¼ of an inch above a bud facing out from the plant.

A partially opened flower may remain darker and better-preserved than a fully open flower. If you’re buying the roses from a store and can’t find any dark varieties, choose roses with velvety petals. This texture will make them appear darker. [14] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source

Flower preservative is available from florists and nurseries. Homemade solutions involving acid and sugar may have a similar effect. For more advice on keeping cut roses in water, read this article.

Do not try to dust the flower first, which can easily damage the petals.

If cutting the roses yourself, use disinfected gardening shears. Scissors may crush the stem, preventing uptake of water and dye. Cut roses at a 45º angle to allow for more surface area for water and dye uptake.

Add flower preservative as well for a longer lifespan.

If the flowers are blotchy, leave them in plain, warm water overnight to spread the color more evenly. [16] X Research source