How to Plant, Grow, and Care for Dioon Edule
Dioon edule is a fascinating cycad and one of the most cold-hardy cycads out there. This cycad will add texture and form to any garden setting and they grow well in pots. Rachel Garcia explores its care both indoors and outside!

Contents
If you’ve vacationed on the eastern coast of Mexico, you probably came across a Dioon edule. Maybe you mistook it for a palm tree or even a fern. What you saw is actually a cycad species that’s been around for longer than humans – or even dinosaurs – walked the earth!
Dioon edule, also called virgin’s palm, is a large, evergreen cycad. Thanks to its subtropical origins, it’s a drought-tolerant plant that’s also delightfully low maintenance. Virgin’s palm is a staple xeriscaping plant in USDA hardiness zones 9-11. It can be grown in the ground, where it’ll stay for hundreds of years, or planted in containers starting at four inches wide.
Like all cycads, Dioon edule is a gymnosperm. It grows female and male cones that range from two to sixteen inches long. More noticeable is the short, woody trunk that’s topped with a festive fountain of leaves. This cycad will definitely add texture and shape to your landscaping.
In this article, we’ll learn all about the growing habits and cultivation of this collection of native Mexican species. Then, with a warm environment and some patience, you can grow your own!
Plant Overview

Plant Type
Cycad
Family
Zamiaceae
Genus
Dioon
Species
Dioon edule
|
Native Area
Mexico
Exposure
Full Sun to partial shade
Height
8’
Watering Requirements
Low
|
Pests & Diseases
Caterpillar, cycad aulacaspis scale, root rot, fusarium wilt
Maintenance
Low
Soil Type
Well-draining, poor
Hardiness Zone
9-11
|
What is Dioon Edule?
Dioon edule used to be split into two subspecies: edule and angustifolium. However, the latter was recently reclassified as its own species under the Dioon genus (though the two are still very similar).
We’ll focus on care requirements for Dioon edule in this article, though they can probably also be applied to D. angustifolium and other species in the Dioon genus, such as Dioon imbricatum, Dioon aculeatum, and Dioon strobilaceum. It’s also worth noting this same species has the synonyms Macrozamia pectinata, Zamia rigida, and Macrozamia littoralis.
Native Area

This plant goes by many common names, including chestnut dioon, virgin’s palm, palma de la virgen, Mexican palm, Mexican blue chamal, and Mexican fern palm. As you can tell by some of the names, this plant is often confused with palms. The two are pretty unrelated, as palm trees aren’t even gymnosperms (they produce flowers instead of seed cones).
They are cultivated for their edible (yet toxic) roots in some areas of Mexico. Even though they’re considered edible here, it’s best to avoid eating them. The people who historically use the toxic and edible roots have a deep understanding of the correct ways to process the plant before consumption.
Characteristics

The most noticeable thing about Dioon edule is its plume of leaves. These leaves are pinnate, down each side of a central stem. As a whole, each leaf grows up to six feet long.
The semi-glossy, blue-green leaves are very narrow and create a soft look. When they’re young, these basal leaflets are edged with small spines with a sharp point. Below the soil are nitrogen-fixing coralloid roots and a tough taproot that can find water in even the rockiest garden soils.
Dioon edule can grow up to eight feet tall (and they aren’t even the tallest cycads!). However, they grow very slowly, so most cultivated ones are so short that they look more like a bush than a tree in the site where they are initially planted. These slow-growing cycads aren’t in a rush because they can live for over a thousand years.
With such a long lifespan comes a complicated and somewhat unusual means of reproduction. Dioon edule is a dioecious species, meaning each cycad only grows male or female cones. Both must be in close proximity to produce viable seed.
Which sex the cycad is isn’t easily known until the female or male cones develop. Even then, they aren’t easily told apart unless compared to each other (the female cones are generally larger). The female cones contain two ovules and produce paired seeds.
Mexican cycad grows up from the tip with new leaves sprouting from the center, like a succulent’s rosette. Old leaves will eventually fall off from the bottom of the tuft, sometimes leaving a harmless scar on the trunk. Slow-growing female cones will take up residency in the center of the palm-like leaves for a couple of years before releasing their paired seeds.
Endangered

For an evergreen with increasing popularity in gardening, Dioon edule is close to becoming an endangered species. Unfortunately, lots of cycads are already endangered or on the verge of extinction.
These magnificent cycads that survived the mass extinction that took out the dinosaurs may not be able to survive the presence of humans. You can help! By growing a Dioon edule in your garden or collections, you’re doing your part to preserve this beautiful species.
Planting

To plant a Dioon edule, dig a hole slightly larger than the root ball, place it at the same depth it was growing in its container, and backfill it with soil, gently pressing it around the roots. Water thoroughly after planting and then sparingly afterward, allowing the soil to dry out between waterings.
How to Grow
As long as you provide the optimal conditions, this palm-like species will be very easy to grow in your garden. Here’s what you need to know for proper Dioon edule care.
Light

Mexico palmswill thrive in full sun. However, since it’s often grown in hotter climates, they appreciate part shade from time to time. If you’re growing it indoors, you must put your Dioon edule by a sunny window (preferably south-facing). If it lives outside in the garden among a collection of others, place it somewhere with part shade during the hottest part of the day.
Water

Water when the soil starts to dry out. Be very cautious of overwatering your plants, as Dioon edule should never be left sitting in water (especially if it’s in part shade). Cut back on watering during the winter, when the temperature and growth have dropped.
Note that it is only drought-tolerant when well-established. Don’t neglect a young, newly planted cycad. You can go longer stretches without watering when it has gotten its bearings. We recommend you don’t go too long, though, and avoid watering sporadically, as this can stress out any cycad.
This Dioon edule species likes humid conditions but isn’t reliant on them. Either way, you should ensure that there’s good airflow between the leaves. Give it space in a collection. When watering, try to keep the foliage and short, stocky trunk as dry as possible.
Soil

Good drainage is perhaps the most important part of Dioon edule care. These cycads will grow in almost any soil, be it rocky, sandy, or loamy, as long as it drains well. However, any of these well-drained soils also need to hold some moisture. If needed, add some mulch or composted material to keep the garden soil from drying out too quickly.
For container cycads, use a soil mix meant for cacti, succulents, or palms. Ensure that the pot has drainage holes and empty the water-catching tray as needed.
Temperature

Dioon edule hardiness is what sets it apart from other cycads in its family. Despite being native to Mexico, this is one of the most cold-hardy cycads, tolerating occasional temperatures as low as 10°F (-12°C).
Fertilizing

Dioon edule usually grow just fine in poor soils, but their growth will speed up if you provide a collection of some extra nutrients. During the growing months, feed frequently with a lightly-dosed, balanced fertilizer. You can also use sandy compost to boost the garden soil’s fertility.
Maintenance

Your Dioon edule houseplant doesn’t need to be pruned. You should only remove leaves if they’re diseased or infested with pests.
Propagation

Mexico cycads can be propagated by seed, but that would mean procuring both males and females, possibly hand pollinating, and waiting until the female cone unravels and releases its seed. Or, to save time and energy, you can buy a new collection of seeds, soak them, and surface-sow them right away. Although they take a long time to grow, Dioon edule seeds germinate very easily.
If you don’t want to wait so long for an established cycad, vegetative propagation is the way to go. A mature Dioon edule will produce offshoots at the base of its trunk. Using a sharp, clean knife, cut the “pup” off of the parent. If it already has roots of its own, make sure to keep them intact. Set the cutting in a small container filled with one of the well-drained soils you would use for potted established varieties.
Common Problems
As long as you provide the right garden environment, this is one of the easiest cycads when it comes to pest and disease problems. There are only a few things to be on the lookout for.
Growing Problems

Like most drought-resistant varieties, overwatering is a huge cause for concern. Too much moisture in the soil can quickly lead to root rot which in turn leads to stem and leaf rot. It’s hard for it to come back from this, so prevention is key. Before watering, check that the first few inches of the soil is dry first (moisture meters are very handy here). If you accidentally overwater, let the soil dry out for longer than usual before resuming a sparser watering schedule.
Cycads can get sunburned if they get too much sun exposure. Their foliage will turn yellow or pale brown when scorched. This usually happens when it is in direct sunlight and the air is dry and hot (we’re talking over 100°F or 38°C). The damage is usually just aesthetic but can’t be undone. The best you can do for a sunburned cycad is move it to a shadier location in your garden.
If you have a collection that are taller than your Dioon edule, try shading it under them to remedy sunburn.
Pests

Caterpillars are always hungry for some leaves – especially cycads! To save the blue-green leaves from becoming lunch, pick off any caterpillars you see and remove them from the garden. If the problem persists, consider using BT spray or diatomaceous earth.
Dioon edule are also vulnerable to scale insects, particularly cycad aulacaspis scale. This unusual, non-native pest was accidentally introduced to the US in the 90s and has been wreaking havoc ever since. They’ll settle into the lower leaves of a cycad and feed, turning the leaves yellow and brown. You won’t mistake this for sunburn though because their white bodies are very noticeable.
You’ll need to cut off infested leaves and destroy them far away from your garden. Of course, the best method is prevention, which is done by only buying healthy cycads from reputable sellers.
Diseases

Dioon edule is unlikely to have any disease problems. However, if the roots are rotting from overwatering, they may become infected with bacteria or fungi already in the garden planting site. Fusarium wilt, which comes from a soil-born fungus, sometimes affects D. edule’s cousin Dioon spinulosum. If you see spots of browning leaves or other unusual growths, try applying a general fungicide.
Frequently Asked Questions
How fast does Dioon edule grow?
This is a very slow-growing cycad. The short stocky trunk grows so slowly that you’ll usually see it at bush height in a garden. They live for hundreds of years, so they aren’t in a hurry to sprout up.
Is Dioon edule poisonous?
Yes. Though the edible roots have historically been used to make tortillas, the leaves and stems are toxic to humans.
Is Dioon edule sago palm?
No, but they’re both in the cycads family. Sago palm can be recognized by its arched leaves, whereas Dioon edule have flat ones. Sago palm also has a golden-colored female cone while this one is white.
How do you plant Dioon edule seedlings?
Plant them into what will be their permanent home (if you’re growing them outside in your garden). Gently place them in well-draining soil in a location that’s warm and gets plenty of full sun.
How do you plant Dioon seeds?
Soak the hard seeds in water for one to two days and then place them on top of the soil in a small container. Keep the seed warm and moist until it germinates and sprouts (you can move it to the garden later).
Are cycads poisonous to cats?
Yes, in fact these cycads are typically poisonous to all mammals, though they have historically been viewed as edible in certain cultures.