The main difference between the two plant species is the leaf shape and coloration. The Philodendron Black Knight leaf is described by many botanists as being heart-shaped, with a shiny dark green coloration.
The Black Cardinal leaf, on the other hand, is slightly oval-shaped, with a mixture of dark green and blackish/red colorations.
There are other differences that will be discussed more in-depth in the content provided below.
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It cannot be stressed enough the importance of the leaf shape for identification. Botanists are keen on the leaf shape of plants for this very reason. The leaf shape for the Philodendron Black Knight and Black Cardinal is key for differentiating as well.
The heart-shaped leaf of the Philodendron Black Night is very noticeable. In fact, some gardeners will agree the shape is the deciding factor of whether or not to make an investment.
The leaf of the Philodendron Black Cardinal is oval, with rounded edges. Some leaves may have a slight tip while others will be smoothly rounded. The Philodendron Black Knight leaf has a pointy tip, with rounded edges.
The Philodendron Black Cardinal leaf ranges between dark green and blackish/red. The natural shine is a sure sign the plant is healthy and thriving. The Philodendron Black Knight leaf is a solid coloration. Depending on the environment and maintenance, the leaves may be a mixture of colorations like the Black Cardinal.
In this case, the coloration may be a mixture of burgundy and light and dark green. Some gardeners have reported colorations, ranging between light green, light brown, and grayish/brown. Again, the natural shine is a sure sign the plant is healthy and thriving.
The dark red and blackish/red colorations are related to anthocyanins. These natural pigments can be modified by acylation, glycosylation, and hydroxylation. So, you can create a mixture of colors.
The Philodendron Black Knight leaf has been recorded at 10 inches (0.25 meters) in length. The length varies between 7 and 10 inches (0.18 and 0.25 meters) in most cases.
The Philodendron Black Cardinal leaf ranges between 8 and 12 inches (0.20 and 0.30 meters) in length. The wide of the leaf can also vary between 5 and 7.2 inches (0.12 and 0.18 meters).
The Philodendron Black Cardinal grows up to 3 feet (0.91 meters) in height. In poor conditions, the growth can be affected, resulting in a much shorter plant. The height of the Philodendron Black Knight has been recorded at 9.8 feet (3 meters).
Like all species of plants, the growth can be stunted due to poor maintenance, such as improper watering and sunlight exposure.
The stem of the Philodendron Black Knight is significantly longer than that of the Black Cardinal. This is obvious by the significant height variation.
The Philodendron Black Cardinal can easily be utilized as a ground cover plant, thanks to its shorter height.
The Philodendron Black Knight width ranges between 1 and 1.6 feet (0.30 and 0.50 meters). The width of Philodendron Black Cardinal ranges between 1 and 1.5 feet (0.30 and 0.46 meters).
Both the Philodendron Black Cardinal and Black Knight are slow-growing plant species. However, the latter is the faster growing of the two plant species.
There is really nothing that can be done to speed up the growth. Philodendrons are notorious for slow growth.
At first glance, it is easy to see why some gardeners would think watering is the same for both plant species. This couldn’t be further from the truth because the watering needs for both plants are significantly different.
The watering needs for the Philodendron Black Knight is average while the Black Cardinal is minimal. Botanists recommend between 0.5 and 0.8 cups of water weekly.
To avoid overwatering, it is recommended to perform the finger soil test in advance. Stick your finger deep into the soil. If significant moisture is noted, repeat the finger test in two more days.
The watering needs for the Philodendron Black Cardinal are minimal. The species is described as a “low-water plant” for this very reason. Perform the finger soil test before watering to avoid overdoing it.
It may take up to two weeks for the soil to dry out enough for more water to be added.
The key to the survival of any plant species is a proper soil environment. Starting with the Philodendron Black Cardinal, which is a low-water plant species, the soil must be well-drained.
To achieve well-drained soil, it is recommended to utilize a mixture of nutrient-rich, organic soil, peat moss, and dry worm casting. It is not necessary to mix the dry worm casting with the organic soil or peat moss. Some gardeners prefer to apply the dry worm casting on top of the soil.
This will help absorb some of the excess water.
Since the Philodendron Black Knight species needs only slightly more water than the Black Cardinal, it is perfectly okay to utilize well-draining soil.
Just as long as you water adequately, well-draining soil will work. In fact, this may be the best soil option since it can prevent water puddling in the soil. Utilize peat moss or coco coir, along with nutrient-rich soil. Dry worm castings can also be utilized to absorb access water.
Indirect sunlight is recommended for both the Black Cardinal and Black Knight plant species. It is recommended to utilize some type of filter to avoid direct sunlight contact.
Partial shade is recommended for the Black Knight and bright light for the Black Cardinal. Again, the plants should not be exposed to direct sunlight in any shape or form.
The Philodendron Black Knight and Black Cardinal will make a great addition to any indoor conservatory, hothouse, nursery, or greenhouse. These plant species are not tolerable to temperatures below 55 degrees Fahrenheit (12.78 degrees Celsius).
To ensure maximum longevity, well-draining soil and an environment with a temperature range of between 55 and 70 degrees Fahrenheit are crucial. Your plants will thrive when properly maintained.