Cycads in my home garden, July 2016

Growing cycads is a labor of love that takes a lot of patience, and failure is common. That is particularly true if try to grow species from around the world since they have a wide range of needs and tolerances. In my home garden here in southern Japan I grow species from the Americas, Africa, Australia and Asia. My success has been, not surprisingly, variable. I grow all of my collection in pots since my garden is quite small and I rent the house.

Here’s what’s going on in my cycad collection this summer, 2016.

Lepidozamia peroffskyana (right foreground), Encephalartos ferox (center), Dioon spinulosum (left back), and Zamia dressleri (pink flushed plant) – all of these plants have flushed new leaves this season except E. ferox. When growing cycads you get used to plants skipping a season for new frond growth.
Dioon spinulosum and Zamia dressleri – both plants have newly flushed growth. The Dioon has a lovely soft blue green color and the Zamia pink-bronze. Both will harden off and mature to dark green.
Zamia dressleri – his species has been really hard to keep here in southern Japan, mostly because of the colder winter conditions, even in the relative warmth of a grow room which occasionally goes down to 5 C – not to its liking. It is said this species also needs a particular mycorrhizal fungus to remain healthy long term. I can only guess this plant was inoculated with the fungus when I got it five years ago.

Zamia pseudoparasitica – probably my best growing Zamia species, tolerating fairly cold temperatures without a problem. In the wild they can be found at high elevation (up to 1000m), so that may be why they can handle cold better than most Zamia. This specimen is finally becoming a near adult.
Zamia integrifolia (AKA floridana) – the famous Florida coontie plant. I thought this species would do well in southern Japan, but it really hates the cold, wet conditions of winter. Even when brought inside they sulk until the real heat of summer hits. These are newly flushed fronds.
Ceratozamia robusta (left) – it is hard to see in this photo, but I have three plants that are very healthy. They tend to flush in late summer to even early winter for me. These are very vigorous and even somewhat cold tolerant, meaning temperatures between 0 and 10 C don’t negatively effect them. Not bad for a tropical species. Cycas debaoensis flushing (right) – this specimen of C. debaoensis is a seedling germinated in 2011. It is finally starting to form a fairly nice caudex (stem).
Cycas debaoensis – the famous multipinnate frond Cycas from southern China. I have found this species reliably hardy down to freezing and enduring long cold conditions quite well. They tend to only flush once a year for me and are therefore quite slow growing.
Cycas panzhihuaensis (left) – a native of southern Sichuan Province in south-central China, this species was hoped to rival C. revoluta for cold hardiness. I can tell you that it isn’t remotely as cold hardy however – those brown pinnae tips are due to a cold snap this past winter that didn’t effect any C. revoluta. Nevertheless, this is a strong growing Cycas with very distinct foliage and growth habit. Dioon edule (right) – the most cold hardy species in the genus and notoriously slow growing. These are newly flushed fronds of two plants from the same seed batch, probably from the San Luis Potosi region of northeast Mexico. Lovely plant, and if kept relatively dry, almost as cold hardy as Cycas revoluta.
Dioon edule (Palma Sola) – the famous relatively fast growing form of the species. These grow at a rate that is similar to Cycas revoluta. Lovely and elegant form, much different than Cycas species.
Encephalartos trispinosus – I got this plant a couple seasons ago, hoping it would be another “cold hardy” cycad for southern Japan. No way, this plant likes heat, like all cycads, and cannot take the combination of cold temperatures and wet conditions without risking fatal rot. I love its blue foliage, but one day had the disquieting realization that it looks terribly similar to an artichoke plant!
Cycas cairnsiana (left) and Encephalartos horridus (right) – two “blue cycads” from different continents, demonstrating the concept of coevolution nicely. The C. cairnsiana is lovely, but like the Encephalartos, it does not do well with wet, cold conditions, so I have to bring both in for winter and keep them dry. Both seed grown and around 4 years old now.
Cycas revoluta v. aurea – Amami Island is home to this famous yellow tipped form of the species. These are newly flushed fronds and already you can see the pinnae tips changing to gold. Some like this coloration, others think it just makes the plant look diseased. Personally, I like the effect.
Cycas revoluta v. variegata – this form has variegation in irregular patches throughout its fronds. Plants with a lot of variegation, particularly more golden in color, are most highly valued in Japan. The plant in this shot has very mild variegation patterns that is more white and therefore a less valuable plant.
Cycas revoluta v. alba – this form flushes brilliant yellow to white to lime green, with the fronds maturing to a bright apple green. This plant has newly flushed fronds, all which are more lime green than white or golden. I’ve noticed that fall flushes are more white in color by comparison, so I’m guessing their color is somehow temperature regulated. A rare form of this species and highly valued in Japan.


6 Replies to “Cycads in my home garden, July 2016”

  1. Hi Botany Boy,

    I found your page when looking for information on growing Bletillas. What a great site!

    Two questions:

    1. I spend winters in Edgewater, FL., Zone 9B. Iwould like to get some Bletiilas established here, but I am wondering if it is too warm. What do you think?

    2. We have a cycad that is commonly known as a sago palm. It has cycad scale. We have been treating it with a dormant oil spray. Any other suggestions?



    1. Eleanor,

      I think you will have a chance with B. striata in Edgewater. The summer should be OK for them, it is the lack of cold in winter that could be a problem. I grew them successfully in Gainesville, Florida for years, though during warm spells in winter they would sometimes begin to grow. Try planting them next to a north facing wall that has no tree cover – that way they will have enough light to grow and flower while not getting too much heat from the sun while dormant.

      Asian scale is bad news in Florida. You can get some ideas from this IFAS pdf: Tom Broome, the famous Florida cycad grower, posted this article about using coffee grounds back in 2007: Many have said this technique doesn’t work, but Tom is a serious cycad grower, so it must have worked for him at some point.

      If your plant is badly infested you may have to cut all the fronds off before treatment. Of course all of these should be carefully bagged and thrown away or burned completely. It will take several applications of insecticide or oil to control them. If there are infected plants in the area they will inevitably infect your plant again. This is a problematic issue for cycad growers in Florida. Sorry that I can’t give you more hopeful news.


  2. Konnichiha Botany Boy,
    I am a japanese, so please forgive my english,

    I was interested in a cycad and arrived in your website.
    I’m surprised at your wonderful collection. Those are very beautiful!!!

    I ‘d like to question you.
    About Z. pseudoparasitica.

    During winter, do you move Z. p to indoor?
    I live in Osaka,USDA ZONE is 9a.
    I think the winter lowest temperature is -2C.
    I ‘d like to grow Z.p at the outdoor.

    1. Hi Takanashi-san! I’m sure my Japanese is worse than your English. As for growing Z. pseudoparasitica outside in winter, I don’t think it is a good idea. I take mine in from late November until mid-April. If you leave them outside they will suffer, lose strength, and even die. The reason is that the average temperature is too low. They need at least 10 C on average to be OK, below that and they will lose strength. They can live at lower temperatures, but only for a very short time. Sorry! Tom

      1. Thank you very much. I’m thankful for your clear answer.I understand.

        I’d like also to know cold resistance of
        I have the strong interest in C.d. , but there are few documents…

        1. To be honest, I’m not sure, but Cycas debaoensis is definitely more cold hardy. I grow it outside here in Fukuoka all year, and my plants are OK. They don’t get colder than -3 C however. I’m not sure about Osaka, but you may be able to grow them well there too.

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