ACNH Flower Genetics Guide
By Paleh
Update: Thanks to data mining from Aeter (Aeter#9823 on Discord), we now know the genes of all the New Horizon flower species! Huge thanks for getting this info! This guide has been updated with all the new gene data for all species.
Animal Crossing New Horizons uses a surprisingly complex genetics system. Every flower has its own unique genes it carries, and you cannot always tell what recessive genes a flower carries based solely on its color. The system uses basic Mendelian genetics, the same system that’s normally taught in school. Since it’s Mendelian genetics, you can also make use of punnett squares to predict offspring.
The gene system is able to record up to 4 different genes for each flower, however most species only use 3, with only roses using all 4.
Flowers from seed bags always have the same genes, so these are vital for being able to predict what offspring you’ll get.
Native flowers found on your cliffs at the start of the game have seed genes, however, since there’s a risk of them breeding before the player reaches them, you should be wary of using them for your breeding if you can’t guarantee the flower isn’t offspring of another.
Hybrids found on mystery islands have different genes than those you would normally get by breeding the seed bag parents. Often these flowers have the genes necessary to produce third/fourth generation hybrids (e.g. blue roses, purple windflowers, etc.). Base color flowers (red, yellow, and white) found on mystery islands have the same genes as seed bags and can safely be used for breeding.
Animal Crossing New Leaf uses an almost identical genetics system as New Horizons. The ACNL version of this guide can be found here.
The genes
Disclaimer: The genes are not labeled in the game’s programming, they’re simply represented by numbers in-game. The labeling here is simply to make it easier to read and understand for players. The game itself only uses binary and 0-2 numbers in the source code. All names and definitions are a matter of interpretation, check the technical explanation section for details on exact implementation.
While four genes exist, only roses use all four. This section will talk about the gene’s general purpose mainly as it applies to roses, but the genes have similar or identical purposes on other species.
The actual displayed color of the flower is based on genes, but when you get to later generations with all of the genes interacting, it’s not always easy to predict which genes will cause which color due to complex gene dominance rules.
If you’re curious what color each gene combination is associated with, there’s a spreadsheet below with the gene values and colors. This can be helpful to look through if you’re trying to make complex breeding plans.
Despite the unpredictability of some gene combinations, there does seem to be a pattern on what each gene does to a flower.
Rr gene
Controls whether a flower is red based or not. Red based flowers are red, black, pink, and orange. Non-red are yellow, white, and purple.
Note: Not all flowers with the R gene will be red-based, since other genes can cover it, but a flower with the genes rr will never be red-based.
RR or Rr = red-based flower
rr = non-red flower
Yy gene
Controls whether a flower has any yellow in it (yellow or orange). Other genes can sometimes cover this gene up though.
The same note for the Rr gene applies here.
YY or Yy = yellow or orange
yy = non-yellow
Ww gene
Controls whether a white flower will be white or show its underlying color: either purple or blue depending on the species.
White flowers are fairly recessive to most colors, so this gene will only have an effect if the white isn’t getting covered by reds, yellows, or other colors.
WW or Ww = white
ww = purple or blue
Technical note: For the W gene only, WW is associated with 00 instead of 11. See the technical explanation section for more info.
Ss gene
Controls which shade the red-based flower will be. Pink is the lightest shade, red is the middle, and black is the darkest. This gene has no effect on non-red flowers.
Note that in species without the S gene, pink is instead obtained by certain interactions between the R and W gene.
SS = pink (sometimes red in some species)
Ss = red
ss = black (or orange when combined with yellow)
Technical explanation
This section is not required to understand the genetics system. It’s meant for those wanting to understand what the game is actually doing behind the scenes. You can skip to the next section if you’re just interested in breeding your flowers.
Every flower has their genes stored in the item’s flag value. The genotype portion of the flag is an 8-bit number. Genes are represented by 2-bit pairs within this flag, and alleles are represented by a single bit within the gene pair. For example, a red rose from a seed bag has the flag value of 11-00-00-01.
For species with fewer than 4 genes, the higher bits are simply always set to 0, with only the lower gene pairs used.
When bred, each parent passes on one random allele from each gene, and they’re combined together to make the offspring’s genes.
For example, if you breed two 11-00-00-01 red roses together, the offspring can be any of the following:
11-00-00-00
11-00-00-01
11-00-00-11
If a flower has a “1 allele” and a “0 allele” on a gene, that gene’s value in the flag is always stored as 01, never 10.
It is also possible for flowers to asexually reproduce under certain conditions, instead of crossbreeding with another flower. This produces offspring with the same genes as the parent, essentially just duplicating/cloning the flower.
Certain areas of the games code also process genes with an alternate “trinary”/numeric format instead of binary, with the following conversion (including genetic notation):
| Binary | Trinary | Genetic |
| 00 | 0 | rr |
| 01 | 1 | Rr |
| 11 | 2 | RR |
This trinary format can be handy for writing out a flower’s genes in a shorthand way. For example, instead of writing out a seed red rose’s genes as 11-00-00-01 or RR-yy-WW-Ss, you can instead just write 2001 to represent the genes.
Important note: Most genes have been labeled where 11 is dominant, however I’ve labeled the W gene opposite, where WW = 00, because the color caused by 11 (purple and blue) behaves similarly to a recessive color. Recessive genes are normally labeled with a lowercase gene name by convention, so I’ve decided to stick with gene naming conventions here. Some guides/tools do not flip this gene, and leave WW = 11, so keep that in mind when looking at other guides and tools.
The genotype flag’s 8 bits are stored alongside other data within a larger flag (currently unconfirmed which of the 3 flags it’s stored in) for an item. The gene order is reversed, so roses are [gene 4]-[gene 3]-[gene 2]-[gene 1], and other species are 00-[gene 3]-[gene 2]-[gene 1].
Flower species
Roses
Roses are the only species to make use of all 4 genes: R, Y, W, and S.
Note: There is only a single gene combo that will display as blue. All other colors could have different underlying gene combinations, but blue’s is always the same. This also means that when you breed two blues together, they will only ever produce more blues.
Seed red = RR-yy-WW-Ss
Seed yellow = rr-YY-WW-ss
Seed white = rr-yy-Ww-ss
Red + yellow: orange = Rr-Yy-WW-ss (50% chance)
Red + red: black = RR-yy-WW-ss (25%)
Red + red: pink = RR-yy-WW-SS (25%)
Red + white: pink = Rr-yy-**-Ss (50%, W gene can be anything)
White + white: purple = rr-yy-ww-ss (25%)
Black + yellow: orange = Rr-Yy-WW-ss (100%)
Orange + purple: “hybrid red” = Rr-Yy-Ww-ss (25%, note: another 25% of the red offspring will not be hybrid reds)
Hybrid red + hybrid red: blue = RR-YY-ww-ss (1.6% / 1 in 64)
Mystery island orange = RR-YY-Ww-Ss
Mystery island pink = RR-yy-ww-SS
Island orange + island orange: blue = RR-YY-ww-ss (6.25%)
Island orange + island orange: special red = RR-YY-ww-Ss (12.5%)
Special red + special red: blue = RR-YY-ww-ss (25%)
Blue rose method
This genetics system explains why blue roses are notoriously difficult to get. Blue roses only ever have the genes RR-YY-ww-ss, never anything else. This means they need genes from red, yellow, and white, hence why crossing purple and orange sometimes works. However, only half of the reds produced will have the required Rr-Yy-Ww-ss genes. The other half will be Rr-yy-Ww-ss, which are incapable of producing blues, and there’s no efficient way to test which is which. Furthermore, even with good reds, only 1 in 64 of the offspring will be blue.
The quickest and most surefire way of getting blue roses in New Horizons is by using Mystery Island oranges, however you can only find these if roses are your native or sister flower (i.e. the ones that spawn on your cliffs, or the ones Tom Nook gives you seeds for), so for many users it’s impossible to obtain these.
There are two alternate paths: one will guarantee you hybrid reds that are capable of making blues (at a very low rate), and the other will gradually increase your chances up to 25% of blue offspring per pairing, to be certain you’ll get blues by the end. The path to increase your chances involves more generations, and test breeding the offspring at one step, but it’s absolutely guaranteed you will get blue roses by the end of this method every time.
It’s currently unclear if the method of increasing chances is faster than simply breeding a lot of hybrid reds and crossing them all with each other, but it is more fool-proof.
Guaranteed blue rose path (v2)
If you’ve already started v1 of this path, you can find the original instructions here. If you haven’t started yet, it’s recommended to use v2 instead.
Note: It’s recommended to have multiple pairs breeding at each step to speed up progress. This means starting with a bunch of whites to get your first purples, and getting multiple offspring per step so you have a reasonable amount of pairs for the next step. The more pairs you have, the faster the process will be.
Important: Due to the duplication mechanic in New Horizons, it’s recommended to use individual pairings (e.g. a single yellow with a single white) rather than any multi-flower layouts like grids or checkerboards, to avoid getting any clones of the parents.
- The first three pairings all use seed flowers only, so it’s recommended to do them all at the same time to speed things up.
- Breed seed white + seed yellow => white0110 (50% chance)
- Breed two seed whites => purple0020 (25%)
- Breed seed red + seed yellow => orange1100 (50%)
- Breed purple0020 + white0110 => purpleX (50%)
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- This is where it gets tricky. Only half of these purple offspring will have the right genes, so you have two options. You can either try your luck and put a bunch of them in a field together, or you can test breed to pick out the ones with the correct genes.
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- To test, breed purpleX + seed yellow.
- Good purple0120 + seed yellow => yellow0210 (50%), white0110 (50%)
- Keep the yellows0210, they can help speed up the next step!
- Bad purple0020 + seed yellow => white0110 (100%)
- If you don’t get any yellows after 3-4 offspring, you can assume the purple is bad and discard it.
- Good purple0120 + seed yellow => yellow0210 (50%), white0110 (50%)
- To test, breed purpleX + seed yellow.
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- You need at least two good purples0120 to continue, but more is better. In New Horizons you can isolate and duplicate your good purples to speed things up.
- Breed two good purples0120 => white*0220 (25%)
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- You can also breed two yellows0210 => white*0220 (25%)
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- Do not cross yellows0210 with purples0120! The white offspring of that pair may have different genes, so keep them separated!
- These whites are very important for increasing your odds in the next steps.
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- Breed orange 1100 + white*0220 => orange1210 (25%)
- If you stop here, you can breed two oranges1210 => blue (6.25%)
- However, continuing to the next step instead will have a 25% of blues.
- Breed orange1210 + white*0220 => red1220 (25%)
- Both the orange and white offspring from this pair are identical to the parents and can be used for breeding if needed.
- Breed two reds1220 => blue (25%)
- Red offspring from this pair are reds1220 and can be used for breeding.
Credit to jpony for suggesting several optimizations to the original method.
If you’re not interested in such a long path, the shorter path that will get you guaranteed “standard” hybrid reds, the kind that have a 1/64 chance of blues. You’ll just need a lot more of them to have any good shot at getting blue.
Guaranteed hybrid red path
Same notes apply from above; the more pairs you have the better, and stick to individual pairings instead of multi-flower layouts to avoid duplication.
- Breed two seed whites => purple0020 (25%)
- Breed seed red + purple0020 => red1010 (50%)
- If available, you can also swap out the seed red for a black from two seeds reds, to increase the chances at this step to 100%.
- Breed seed yellow + red1010 => red1110 (25%)
- Breed two reds1110 => blue (1.56%)
Cosmos
Cosmos make use of 3 genes: R, Y, and S. Despite their simplicity in actually breeding the hybrid colors, cosmos genes are surprisingly odd. Their genes behave a bit differently than other species.
The S gene seems to be almost purposeless. Unlike other species where it’s required for blacks and sometimes pinks, this gene isn’t required for any of the cosmos hybrids. SS flowers are often lighter colors than their Ss and ss counterparts, such as yellow becoming white, or black becoming red, but the gene in general seems rather pointless.
Furthermore, blacks have different genes than you would see in other species. All black cosmos are RR-YY, essentially just concentrated orange. In other species the Y gene has nothing to do with making black.
Nevertheless the crossings to make the hybrids are straightforward and easy.
Seed red = RR-yy-ss
Seed yellow = rr-YY-Ss
Seed white = rr-yy-Ss
Red + yellow: orange = Rr-Yy-Ss / Rr-Yy-ss (100%)
Red + white: pink = Rr-yy-Ss / Rr-yy-ss (100%)
Orange + orange: black = RR-YY-Ss / RR-YY-ss (roughly 6.25%, depending on the parent genes)
Mystery island orange = RR-Yy-Ss
Mystery island pink = Rr-Yy-SS
Island orange + island orange: black = RR-YY-Ss / RR-YY-ss (18.75%)
Lilies
Lilies make use of 3 genes: R, Y, and S.
Seed red = RR-yy-Ss
Seed yellow = rr-YY-ss
Seed white = rr-yy-SS
Red + yellow: orange = Rr-Yy-ss (50%)
Red + red: black = RR-yy-ss (25%)
Red + red: pink = RR-yy-SS (25%)
Red + white: pink = Rr-yy-Ss (50%)
Mystery island orange = RR-YY-Ss
Mystery island pink = RR-Yy-SS
Mystery island black = RR-Yy-ss
Pansies
Pansies make use of 3 genes: R, Y, and W.
Seed red = RR-yy-WW
Seed yellow = rr-YY-WW
Seed white = rr-yy-Ww
Red + yellow: orange = Rr-Yy-WW (100%)
White + white: blue = rr-yy-ww (25%)
Red + blue: “hybrid red” = Rr-yy-Ww (100%)
Hybrid red + hybrid red: purple = RR-yy-ww (6.25%)
Mystery island orange = RR-YY-Ww
Mystery island blue = Rr-yy-ww
Island blue + island blue: purple = RR-yy-ww (25%)
Island orange + island orange: purple = RR-YY-ww (25%)
Island blue + island orange: purple = RR-Yy-ww (25%)
Tulips
Tulips make use of 3 genes: R, Y, and S.
Seed red = RR-yy-Ss
Seed yellow = rr-YY-ss
Seed white = rr-yy-Ss
Red + yellow: orange = Rr-Yy-ss (50%)
Red + red: black = RR-yy-ss (25%)
Red + white: pink = Rr-yy-Ss (50%)
Orange + orange: purple = RR-YY-ss (6.25%)
Mystery island pink = Rr-yy-Ss
Mystery island orange = Rr-YY-ss
Mystery island black = RR-Yy-ss
Island black + island black: purple = RR-YY-ss (25%)
Island orange + island orange: purple = RR-YY-ss (25%)
Island black + island orange: purple = RR-YY-ss (25%)
Hyacinths
Hyacinths make use of 3 genes: R, Y, and W.
Seed red = RR-yy-Ww
Seed yellow = rr-YY-WW
Seed white = rr-yy-Ww
Red + yellow: orange = Rr-Yy-WW (50%)
Red + white: pink = Rr-yy-Ww (50%)
White + white: blue = rr-yy-ww (25%)
Orange + orange: purple = RR-YY-WW (6.25%)
Orange + orange: special blue = RR-Yy-WW (12.5%)
Mystery island blue = RR-Yy-WW
Mystery island pink = Rr-yy-Ww
Mystery island orange = Rr-YY-WW
Island/special blue + island/special blue: purple = RR-YY-WW (25%)
Island orange + island orange: purple = RR-YY-WW (25%)
Island/special blue + island orange: purple = RR-YY-WW (25%)
Mums
Mums make use of 3 genes: R, Y, and W. The W gene seems to work oddly in this species. Normally, the white + white color (purple in this case) requires ww. However, in this species, certain combinations of the R and Y gene can also cause purple even with WW or Ww genes. This species is also odd in that it is the only species to have green flowers. Green mums are genetically similar to purple tulips.
Seed red = RR-yy-WW
Seed yellow = rr-YY-WW
Seed white = rr-yy-Ww
Red + white: pink = Rr-yy-WW/Rr-yy-Ww (100%)
White + white: purple = rr-yy-ww (25%)
Red + yellow: “hybrid yellow” = Rr-Yy-WW (100%)
Hybrid yellow + hybrid yellow: green = RR-YY-WW (6.25%)
Hybrid yellow + hybrid yellow: “special purple” = RR-Yy-WW / Rr-YY-WW (25%)
Special purple + special purple: green = RR-YY-WW (25%)
Mystery island pink = Rr-Yy-ww
Mystery island purple = RR-Yy-Ww
Island purple + island purple: green = RR-YY-WW / RR-YY-Ww (18.75%)
Island purple + island pink: green = RR-YY-Ww (6.25%)
Windflowers
Windflowers make use of 3 genes: R, Y, and W. However, because orange windflowers take the place of yellows, it may be more fitting to call the Y gene the O gene instead for this species.
Seed red = RR-oo-WW
Seed orange= rr-OO-WW
Seed white = rr-oo-Ww
Red + orange: pink = Rr-Oo-WW (100%)
White + white: blue = rr-oo-ww (25%)
Red + blue: “hybrid red” = Rr-oo-Ww (100%)
Pink + blue: “special pink” = Rr-Oo-Ww (25%)
Pink + blue: “hybrid red” = Rr-oo-Ww (25%)
Hybrid red + hybrid red: purple = RR-oo-ww (6.25%, O gene can be anything)
Special pink + special pink: purple = RR-**-ww (6.25%)
Special pink + hybrid red: purple = RR-**-ww (6.25%)
Additionally, half of the blue offspring from two hybrid reds will be special blues with the genes Rr-oo-ww, which have a 25% chance of producing purples when bred together. You can tell these special blues apart from normal blues by test breeding with a seed orange. Special blues will produce pinks 50% of the time, normal blues will only produce oranges. It’s not yet clear if this method is faster, but it is an alternate method of increasing your chances if you’re struggling to get purples.
Mystery island pink = RR-OO-Ww
Mystery island blue = Rr-oo-ww
Island pink + island pink: purple = RR-OO-ww (25%)
Island blue + island blue: purple = RR-oo-ww (25%)
Island blue + island pink: purple = RR-Oo-ww (25%)
Breeding tips
Spawn mechanics
Update: A lot of new info has been discovered about spawning mechanics recently! This section will be updated with the info soon.
A new mechanic that’s been introduced in this game is flower cloning/duplication.
Flowers are now capable of duplicating themselves when they’re watered. This can only happen in cases where the flower is either not touching another flower, or any flowers that it’s touching have already bred with different partners. A flower will not duplicate if it’s touching a valid partner that has not bred yet.
Furthermore, tests so far seem to imply that the amount of empty spaces around a flower does not affect the spawn rate. As long as there’s at least one empty spot for offspring, the parents will breed at the same rate as it would if all other spaces were open. However more testing needs to be done to determine the exact factors the game is taking into account when deciding if a flower breeds that day or not.
Unlike in New Leaf, New Horizons has no set limit on how many new child flowers can spawn in a day. This means that the more flowers that have the potential to breed in a day, the more offspring flowers, so it’s best to make more plots or bigger fields when possible.
It’s also worth noting that it seems flowers don’t progress through their growth cycle when planted on the beach. So sprouts will stay sprouts, and buds will stay buds. It’s unclear if they will breed on the beach if they’re in flower form and watered, but picking flowers and placing them on the beach is a good way to temporarily store non-breeding flowers without worrying about accidental breedings. The same unfortunately does not apply to sand paths, which flowers will grow and breed on.