"Bulletproof" Cycads
By Jody Haynes
(20 August 2000)

The term "bulletproof," as it is used in the horticulture industry, is typically applied to plants that are extremely hardy and that require very little or no supplemental irrigation or other type of maintenance. I have heard this term applied to cycads such as the cardboard 'palm' (Zamia maritima, recently changed from Z. furfuracea [Schutzman & Dehgan, in press]), the virgin 'palm' (Dioon edule), and the Florida coontie (Zamia floridana), but a recent experience made me aware of another cycad worthy of the term "bulletproof." In this article, I will summarize this experience and then justify the title "king of bulletproof cycads" for Zamia loddigesii.

As most cycad collectors know, Z. loddigesii is not a species that is much sought-after. It is a fairly nondescript plant from Mexico that somewhat resembles a narrow-leaflet form of Z. maritima (Figs. 1 & 2). It generally does not hold as many leaves as Z. maritima or Z. floridana; it does not attain the impressive size of sago 'palms' (king sago = Cycas revoluta; queen sago = C. rumphii); and it does not have the cold-hardiness of D. edule. As a result, it has not received much attention from the landscape industry in Florida. But, as a budding cycadaholic, I guess I will try just about anything...
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Figure 1. Small adult female Zamia loddigesii in cone.	Figure 2. Closeup of Zamia loddigesii female cone.

Last November I acquired over 300 bare-root Z. loddigesii plants (which came out of 1-gallon containers) from a friend in central Florida. I potted them up in 2-gallon containers using Tom Broome's 4:3:2:1 soil mix and Nutricote 270. About the same time, I also acquired 30 bare-root D. edule seedlings and a liner tray (38) of wide-leaflet coontie seedlings, which I potted up just as I had the Z. loddigesii. Also about the same time, I potted up around 50 seedlings of Z. maritima that had self-seeded in my yard. One thing I noticed shortly after potting the Z. loddigesii was that almost all of the plants had dropped their leaflets; I attributed this to the stress of being bare-rooted. Conversely, the D. edule seedlings (which were also acquired bare-root) did not lose their leaves and appeared healthier overall.

In March of this year, all of these plants were moved onto wooden pallets in partial sun at a friend's field nursery and were virtually neglected until about a week ago, when I finally made time to tend to them (I'm a bad boy...I know!). I need to stress here that all of these plants were potted in the same size container at around the same time and using the same soil, and that they were all fertilized with the same fertilizer. Also, they were all healthy in March when I moved them to the field nursery, where they have since experienced basically the same environmental conditions (i.e., very little supplemental irrigation and absolutely no weeding) over the past six months.

Needless to say, I was expecting the worst upon my arrival at the field nursery last weekend--and initially I was not disappointed! What I encountered was a patch of weeds--some of which were over three feet tall--where my cycads once were (Fig. 3). After weeding all of the containers (which took about 3 hours; Fig. 3), the differential survival/health status of the four species was somewhat shocking. The results of this 'experiment' are as follows:

1. About 70% of the Zamia maritima plants had died, apparently from a lack of water during the drought this spring

2. Three of the 30 Dioon edule plants had died (10%), probably for the same reason

3. Two of the 38 Zamia floridana plants had died (5%), again probably from lack of water

4. Every single Zamia loddigesii plant (over 300 of them) was alive and thriving (100% survival)!

As you can see from the above results, Z. loddigesii out-performed the other "bulletproof" cycads by a fairly wide margin. Although this species may not exhibit qualities necessary to make it a 'bread-and-butter' landscape plant for Florida, it is certainly a hardy plant that can tolerate drought; furthermore, it has no significant pests or diseases and grows well with only a single annual application of slow-release fertilizer. As a result of this experience, I plan to begin recommending Z. loddigesii to the participants of the Florida Yards & Neighborhoods program that I head up here in Miami-Dade County as a tough and durable, drought-tolerant plant that, when planted with other drought-tolerant plants, has the potential to dramatically reduce water, fertilizer, and pesticide usage in south 'Florida Yards'.

Reference

Schutzman, B., and B. Dehgan. In press. Taxonomic problems and solutions in Mesoamerican Zamia (Zamiaceae, Cycadales). Proceedings of the 1999 International Symposium on Cycad Biology, Miami, FL.
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Notes:	(1) I realize that I did not treat these cycads properly over the past few months and I do plan to remedy this situation. However, I assure you that my rare cycads and those in my ex-situ "seed" colonies have received much better treatment!
	(2) Florida Yards & Neighborhoods is an educational outreach program of the University of Florida that is being offered by Cooperative Extension offices in many counties throughout the state.

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