Apples vs Crabapples

I created a project to track apples and crabapples in ND and SD. Since they are all Malus, I would like a way to distinguish apples from crabapples. And since there are a lot of crabapples being submitted, I’m wondering how I could distinguish them. Would it be best to use an observation field? Should I use fruit size as a field. I’m just not sure the best way to do this. Look forward to suggestions.


People with more horticultural experience, please correct me.

Apples are interesting… if you plant a seed from a store-bought apple, you’ll end up with a crab apple because the seeds are formed by sexual reproduction whereas store-bought varieties are just either cuttings or grafts taken from the first Granny Smith apple tree, or subsequent clones, for example.

How do you figure which is which? If it’s farmed commercially, apple. If someone knowingly planted a cutting or graft from a commercial veriety in their garden, apple. If it sprouted from seed: crab apple.

Both are perfectly safe to eat when ripe, but the crab apple won’t have the same genes as the parent from which it was seeded.

Knowing this, next time anyone offers to pick something up at the local garden center, ask if they could pick up some apple seeds…

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Conventional apples should all be identified as Malus domestica, I think?

I think you need to read Chapter 9 of this excellent book :)


The best way to approach this might depend on what you want to do with your observations. Are you looking to display the results in a project, export data, etc.? You can also post a link to the project so folks can potentially see what you are working with.

I would guess that an observation field might be what you want to use, though I can’t tell about the fruit size one in particular. Many fields have generic names but are used for some specific thing that isn’t always obvious. You can check out the response options for that field and see if it matches what you need. You could also search through other existing fields (once iNat is back online) to see if there’s another that would meet your need or create your own if there isn’t.

I don’t get it, from what I read crab apples is what apples with smller fruits are called (I honestly hear about it for the first timeКребы), like Malus baccata? But what will grow from a seed is what is called a wild-type apple, it will have big apples, but they will be pretty sour, it won’t look like species and hybrids with small fruits.

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that seems like an interesting project. may i ask why you’re tracking apples vs crabapples?

people purposely plant commercially crabapple cultivars, too. they can make nice patio and general landscape trees.

i believe any apple (fruit) smaller than 2 inches, or 5 cm, will generally be referred to as a crabapple by horticultural folks.

i’ve never done it myself, but my understanding is that because apples don’t grow “true” from seed, the apples you get from trees that you grow from seed can be quite variable, though they do tend to fall below the 2-inch threshold and are usually tart, even if the source fruit was much bigger and sweeter.

there are wild apple species, too, which are also commonly referred to as crabapples, but it doesn’t look like any of those would occur (or else would occur only rarely) in the Dakotas:

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I am suggesting people enter the “Cultivar” name if known in the observation data. But there are so many apples where people don’t know the variety of the apple. And then there are ornamental crabapples and edible crabapples and edible apples and some even use the term apple crab for those fruits that are bigger than crabapples and smaller than conventional apples. I’m thinking a fruit width observation field would be good if people measured.

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That is true. Maybe that is how I could distinguish apples from crabapples. From what I know, apples are a mix of genetics but M. domestica is an accepted taxon.

The reason I created the project is to keep track of any apple varieties I find in my area. Some are edible crabapples and some are edible apples but then there are also ornamental crabs. There really isn’t any good way to differentiate them. That is why I’m thinking fruit width size might be a good way to do it. I’m thinking using centimeters would be best.

Apples are really complicated. Seeds from an apple or a crabapple will normally produce something different than the parent if it is cross pollinated by a different variety which is usually the case. There are some apples that grow true to species like Malus ioensis (native Iowa crabapple) but most things people grow in their gardens are a mix of genetics. I think Malus is so different than other genera. Some apples can be assigned a genus and species name but I think most cannot.

Why? What will it tell me.

The Iowa crabapple is known from S. Dakota, but I think it’s quite rare and may be extirpated now. I’ve also thought of expanding this project to include more states. I just think Inaturalist is the best place to document apples (wild and planted) as you can upload pictures and it records location. I haven’t found any other tool that would be good for this.

i think there are 2 things to consider:

  1. if the fruit is still developing, the size of the fruit may not be a good indicator of apple vs crab apple. so you might need a secondary field to record whether the fruit was ripe or not (or unknown), or request the size only from ripe fruit.
  2. if you want to be able to query for sets of observations, it might be best to set up this field as a set of ranges (ex. up to 5cm / greater than 5cm / not able to determine), rather than allowing any numeric input. (the system doesn’t have a built-in way to sort based on observation values. so you’d have to do that outside of the system.)
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You are sooooo smart. I never thought of that. Yes, the fruit must be mature and a range of values makes way more sense. I’m wondering if I use something like Pea sized, dime sized, quarter sized, golf ball sized, etc…I’ll have to think about this some more. But I LOVE your idea.

Something akin to this but with a lot more detail. The genetic history of cultivated apples is quite distinct from that of crabapples, although of course the two have hybridized many times.