Know Your Green Dragon: Arisaema Dracontium vs Pinellia Pedatisecta

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Robert Pavlis

Who wouldn’t want a green dragon in the garden? The problem is that some green dragons are native to North America (Arisaema dracontium) and others are not (Pinellia Pedatisecta). Pinellia is commonly sold as Arisaema dracontium, and since Pinellia is much more aggressive it can take over native areas after well intentioned gardeners plant it.

If you grow either of these plants, make sure you know which one you have.

There is nothing wrong with growing Pinellia in North America; just make sure you label it correctly, and don’t plant it in wild areas.

Know Your Green Dragon: Arisaema Dracontium vs Pinellia Pedatisecta
Know Your Green Dragon: Arisaema Dracontium ripe fruit, source: ozarkedgewildflowers

Comparing Arisaema Dracontium and Pinellia Pedatisecta

I got a “native” green dragon from a local plant sale and it has been growing for a couple of years. It is starting to spread a bit too much for me and I was thinking of moving it to my sugar bush (mostly sugar maples). A friend was by from BotanyCa, a specialty seed house, and we discussed the plant. She took some pictures and soon confirmed that this was not Arisaema dracontium. What!! How could that be?

As it turns out I also have a couple of pots of Arisaema dracontium that I have been growing from seed and they are now flowering. I think they flowered last year for the first time.

Plant Science for Gardeners by Robert Pavlis

I used these two plant sources for the pictures in this post.

We think the Pinellia is pedatisecta. It is the more popular one and it fits the description. At some point I will key it out and update this post if the species name is wrong. It is certainly a pinellia.

I then checked with a number of other authoritative sites that compared these two plants and assembled a list of ways to ID one from the other. The following is a list of those comparisons and my observations.

Arisaema Dracontium is Taller

The documented sizes for these plants is all over the map. Some have the arisaema taller and others the pinellia taller, but most sources say pinellia is smaller.

A. dracontium is reported to grow as tall as 3 feet. The leaves on my plants are already 1.5 ft tall (it is still in the seedling pot).

The height of pinellia leaves are about 1 ft tall.

The Pinellia Flower Reaches Above the Leaves

The first pinellia flower of the season develops before the leaves and grows taller than the leaves. Pinellia can flower several times during the summer and each flowering is taller than the leaves.

Arisaema dracontium has it’s flower below the leaves although the top of the spadix may reach slightly above them. It only flowers once a season and the first flower forms after the leaves show.

Arisaema dracontium, flower opens below the leaf, source Garden Fundamentals
Arisaema dracontium, flower opens below the leaf, source Garden Fundamentals
Pinellia pedatisecta, flowers open well above leaves, source Garden Fundamentals
Pinellia pedatisecta, flowers open well above leaves, source Garden Fundamentals

Arisaema Dracontium Flowers On the Main Stem

The flower peduncle in A. dracontium starts part way along the pseudostem holding the leaf. In pinellia, the flower peduncle develops right from the tuber. The leaf petiole and peduncle grow out of the ground as separate organs.

Arisaema dracontium, flower stem branches off main stem above ground, source Garden Fundamentals
Arisaema dracontium, flower stem branches off pseudostem above ground, source Garden Fundamentals
Pinellia pedatisecta, flower stem originates below ground, source Garden Fundamentals
Pinellia pedatisecta, flower stem originates below ground, source Garden Fundamentals

When the flower is finished, and if it’s pollinated, the pinellia flower bends over towards the ground in contrast to arisaema, which remains vertical. Unfertilized arisaema flowers, including male only flowers, also bend towards the ground as shown in this young seedling.

Arisaema Dracontium vs Pinellia Pedatisecta, unfertilized arisaema flower
Arisaema Dracontium, unfertilized flower on a seedling, flowering for the first time, source Garden Fundamentals

Central Leaflet in Pinellia is Longer

Both plants have similar looking compound leaves with numerous leaflets. Some believe arisaema is a bit darker green and pinellia a more yellow-green. This might be true, but not a reliable way to identify these plants. The edges of pinellia leaflets are wavy; arisaema are smooth.

The length of the center leaflet can however be used. This leaflet on pinellia is longer than the leaflets on either side of it. This is true for both more mature plants and smaller immature plants. The center leaflet in A. dracontium is slightly smaller than its neighboring leaflets

Arisaema dracontium, leaves , source Garden Fundamentals
Arisaema dracontium, central leaflet is about the same size as the neighboring leaflets, source Garden Fundamentals
Pinellia pedatisecta, center leaflet is longer than the others, source Garden Fundamentals
Pinellia pedatisecta, central leaflet is longer than the others, source Garden Fundamentals

Pinellia Pedatisecta Spreads Faster

Pinellia are known for spreading by both offsets and seed, and P. pedatisecta has a reputation of being one of the fastest spreaders. This is why identification of this plant is so important.

Arisaema dracontium spreads too slowly for most gardeners, but it is easy to grow from seed.

YouTube video

Fused Jacks?

I am talking about fused jacks, not confused jacks. Spadix is the proper name for the “jack” in these plants, and in arisaema, it is free from the spathe (the pulpit). In the picture below I removed the spathe that was not fused (attached) to the spathe and you can see it is all gone. In contrast, the back of the spadix in pinellia is partially fused to the spathe. In the picture below I removed the unattached part of the spathe.

Arisaema dracontium, spadix is not fused, source Garden Fundamentals
Arisaema dracontium, spadix is not fused. Full flower on the left, spathe removed on the right  source Garden Fundamentals
Pinellia pedatisecta, showing fused spadix, source Garden Fundamentals
Pinellia pedatisecta, showing fused spadix, the free part of the spathe has been removed, source Garden Fundamentals

Sex and Jacks

Arisaema can be male or female – they are dioecious. Even more interesting is the fact that a given arisaema plant can change its sex from year to year.

Pinellia are monecious. The flower has both male and female parts in the same flower.

The difference between these two flower forms is easily seen in the closeup pictures above. Pinellia has two sections, each with different structures. Arisaema has one type, which I believe is male.

Arisaema Dracontium Forms Red Fruit

The fruit of arisaema is red and each fruit can contain more than one seed.

The fruit of pinellia remains green or whitish-green and each fruit only has one seed. This is true of all pinellia species.

The leaves of arisaema die back in late summer (September) while the leaves on pinellia stay green late into the fall.

Pinellia Pedatisecta Forms Round Tubers

The offsets from the mother tuber are round in pinellia and pear shaped in arisaema. As pinellia grows. the offsets fuse together forming a large single tuber as shown below. I am not sure if A. dracontium does the same (my plant is still too small).

Arisaema dracontium tuber, in fall showing a separated pear-shaped offset
Arisaema dracontium tuber, in fall, showing a separated pear-shaped offset
Pinellia pedatisecta, two fall tubers showing the round offsets
Pinellia pedatisecta, two fall tubers showing the round offsets
Pinellia pedatisecta, a larger tuber (about 3 years in my garden) showing how the offsets fuse together
Pinellia pedatisecta, a larger tuber (about 3 years in my garden), top view, showing how the offsets fuse together
Pinellia pedatisecta, a larger tuber (about 3 years in my garden) showing how the offsets fuse together
Pinellia pedatisecta, the same tuber showing bottom view

Comparing Arisaema Dracontium and Pinellia Pedatisecta

The two species seem to have several differences that make identification fairly easy. If gardeners take the time to look at them, it should be easy to distinguish one from the other.

Please check your plants so you don’t spread misnamed plants or seeds.

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

7 thoughts on “Know Your Green Dragon: Arisaema Dracontium vs Pinellia Pedatisecta”

  1. I really appreciate your detailed analysis of the diffrences between these 2 species. Just the kind of information I need to be sure the green dragon that voluntarily came up in my woods is our native. However, I must say that the sheer volumne of addes interrupting your text and the fact that several were videos was extremely disruptive and a strong deterrant to me ever using your web site again. Thought you might like to know.

    Reply
  2. Still trying to.figure out which one I have but it definitely likes where it is as there are a lot of nutlets from parent. Berries turn red after flowering but still confused because it seems aggressive as it is in multiple planting beds in my back yard

    Reply
  3. I appreciate the information. I have a huge problem with the pinnelllia spreading in my garden. I can’t get rid of all the little plants, which are unfused and sitting on small onion-like baby bulbs. Some of the larger ones are on round tubers, which are easy to remove. I am wondering if there is a good strategy for selective herbicide application. I have several hundred plants growing that came in a pot of something else I bought at a garden sale.

    Reply
  4. Very detailed article with great pictures. Thanks for taking the time to clarify on the these two fairly similar looking species

    Reply

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