Updated: Mar 8
Important message before reading this blog: This is a product of my own researches and therefore my own opinion.... Im not a Hoya expert so this is not an expert opinion.
I think Hoya carnosa species is the most complicated Hoya species. Perhaps because it is the oldest of all the Hoya species, a lot of varieties and cultivars were cultivated or created from this species. And then these cultivars were shared by/to different hoya enthusiasts in different places in the world and then out of these cultivars, hybridizers develop or created more varieties. According to what I have gathered, there are three groups of Hoya carnosa varieties:
1. Hoya carnosa exotica variety
2. Hoya carnosa variegata variety
3. Hoya carnosa Tricolour variety
From the original carnosa , hybridizers created Hoya compacta, Hoya Krinkle 8, Hoya chelsea and other cultivars like Snowball, Carnosa alba, Carnosa red etc etc. Then they created the Hoya carnosa exotica varieties and the Hoya carnosa variegata varieties. Examples are the Krimson Princess and then the Krimson Queen.
How do you differentiate a Krimson Princess from a Krimson Queen ? If the variegation is inside, it is the Krimson Princess and if the variegation is outside or along the margin of the leaves, then it is Krimson Queen.
In one of my researches, I have found an easy way to remember the distinction between Krimson Queen or Krimson Princess:
“The queen wears her white like a crown (the leaf edges are white, like a silver crown) while the Princess wears her white like a gown (white in the middle, edges or margins are green). “
Moving on with the discussion: you would think that hybridizers will be content after creating these Hoya carnosa variegata varieties, but no, they keep inventing and they keep cultivating.
The hybridizers created the Tri-color varieties to solve the problems of the albino in the variegata variety. Albinism as you may know, although really pretty, is not good. Albinism in plants interferes with photosynthesis, which can reduce survivability. Eventually your plant will die if it keeps growing white leaves because the plant is not creating enough food to sustain itself, so the plant will become weak and then eventually will die.
Below is a Hoya carnosa Krimson Queen producing albino leaves (Photo not mine, grabbed from the internet).
In this tri-colour variety comes the answer to your question why you have a Hoya carnosa Krimson Queen with pink leaves, and the KP with the darker almost red leaves. The hybridizers wanted more beautiful and stronger, healthier variegated Hoya carnosa that’s why they created new varieties. One of them is what is now called Hoya carnosa “Rubra” and a lot of other varieties like the Hoya carnosa Brazil, Hoya carnosa Suzie, Hoya carnosa variegata "Purple Pride" and other beautiful varieties.
Excerpts from the Publication of the Hoya carnosa “Rubra”. (Note: I only copied the easier part to understand) - You may skip reading this bit if its too much for you to read.
Plants of the Hoya carnosa Tricolor variety have variegated leaf blades which are similar in pattern to those of the Hoya carnosa Variegated variety but are preferred because of certain characteristic colors which, in immature and newly matured growth, appear in the albino or variegated areas of the leaf blades.
Plants of the Hoya carnosa Exotica variety have variegated leaf blades but in contrast to the albino leaf blade border areas of the Hoya carnosa Variegated plant variety are characterized by an albino center field in the leaf blade.
The main object of the invention has been to develop a plant variety which is related in general appearance to the Hoya carnosa Exotica plant variety but which exhibits colors in the albino leaf blade areas that are similar to those found in the Hoya carnosa Tricolor variety. This new plant invented is called Hoya carnosa “Rubra”.
Plants of the new variety generally resemble plants of the Hoya carnosa Exotica variety and are not only related to this variety but also related to the Hoya carnosa Variegata and Hoya carnosa Tricolor varieties. The new variety is mainly distinguished from its antecedents and related varieties known to the inventor by a combination of certain color and structural characteristics which will be apparent subsequently. The new variety appeared as a sport on a plant of the Hoya carnosa Tricolor variety which was under cultivation in a nursery at Winter Garden, Fla, and since the initial discovery of the new variety,has been asexually reproduced by the inventor at the Winter Garden nursery by the propagation of stem cuttings taken from the original plant.
Through successive propagations it has been ascertained that plants of the new variety generally resemble plants of the Hoya carnosa Exotica variety but are distinguishable from this plant variety and from other related varieties known to the inventor by a growth habit which combines the following characteristics:
(1) Larger diameter stems than those of the Hoya carnosa Exotica variety and which in color are dominated by purple, purplish red, red, reddish brown and/or pink hues prior to becoming glaucous;
(2) Leaves with petioles that in color are dominated by purple, purplish red, red, reddish brown, pink and/ or yellowish pink hues prior to becoming glaucous, and with leaf blades that are somewhat broader than those of the Hoya carnosa Exotica variety, that are variegated in patterns characteristic of the Hoya carnosa Exotica variety, that have an albino center area which in color is dominated during early immaturity by purplish pink, purplish red, red and/or yellowish pink hues, and that have a green border area which is overcast during early immaturity with color endowing the border area to the ordinary eye with a blackish and/or brownish appearance; and
(3) An inflorescence that has a peduncle color dominated by purplish red, red and/or reddish brown hues prior to becoming glaucous, a pedicel color dominated by purplish red and/ or red hues, a sepal color dominated by purplish red, red and/or reddish brown hues, and a petal which in color at its upper epidermal side is dominated by purplish pink and/ or pink hues and which in color at its lower epidermal side is dominated by a purplish red hues.
Photos of my own Hoya carnosa "Rubra"
Now back to my blog for additional information and photos:
1. Hoya carnosa variegata Purple Pride (Photo not mine, from the internet)
2. Hoya carnosa Brazil (cross between Hoya compacta and Hoya carnosa variegata) -photo from internet.
UPDATE 9 May 2020:
Last month, I was told that this Hoya carnosa "Brazil" is simply a variegated Hoya carnosa "Krinkle 8".
As of this writing, 9 May 2020 I was told this is not any of the above but a seedling of Hoya compacta x variegated Hoya chelsea (cv. Chelsea is either a sport or seedling of cv. Krinkle 8.)
I therefore give up hahaha ! I dont care anymore.
3. Hoya carnosa Krinkle 8 albomarginata aka Hoya carnosa Suzie Q
5. Hoya carnosa Krinkle 8 variegated
How do hybridizers create these new varieties? By taking a sport (a part of the plant that is showing different characteristics from the mother plant) they do vegetative propagation of up to six times until the traits they want to create becomes dominant.
Will these variegated genes be stable? No, because they are created and not genetic. The sport where they came from was produced by random mutation, and it is often difficult to stabilize so they will have tendency to revert back to its original source. A Hoya carnosa Rubra can be an Exotica if you let the exotica genes dominate your plant and it can revert to green or ordinary Hoya carnosa if you let the green genes dominate your plant.
So are they the same or different? My opinion is they are the same! The hoya carnosa variegata is the same as the Hoya carnosa Rubra. And the Hoya carnosa albomarginata is the same as the Hoya carnosa Tricolour and Krimson Queen because they all are from one species, the grandmother Hoya aka Hoya carnosa. The varieties are created because we are not satisfied with what we have, so we keep on adding something new. But they are from one species only so no matter what name you attach to them, they will always be a Hoya carnosa. There are more than 500 other Hoya species that you can focus your attention to, don’t be too consumed by just one Hoya species.
As always,if you feel that I am incorrect in any of my assertions or observations, or if you have other information not in this write-up, please feel free to contact me and I'll be happy to change/edit and add to this write up. This page is for all Hoya lovers, this is for sharing knowledge and not discrediting someone else's knowledge. You are reading this because you have the same passion as me, the love of Hoyas.
Sharing the Hoya love…. Ces Bartz of Hoya Obsession NZ.