Note from ideasguy
I edited this topic:
http://www.flowergenie.co.uk/ideas/forum/index.php/topic,1373.0.html
to create this new topic to give this discussion on Cycads a dedicated topic. Looks interesting, Malcolm and Monica 
Oh My, Malcolm,
Cycas panzhihuaensis is one lovely looking cycad. Those glaucous fronds make me quiver. All the cycads are outrageously expensive because not a one of them really grows fast - no matter what suppliers try to assure us, plus suppliers of newer cycads now have to jump through lots of CITES Appendix 2 hoops (Endangered Species). No one I know has
panzhihuaensis, but they are available locally (for me, that is). And since
C. revoluta is so over-used here,
panzhihuaensis would really be a knock-out. I have just the spot....thanks for pointing that one out! Check out these beauties in Miami:
http://davesgarden.com/guides/pf/showimage/27945/Since it was only collected in 1979 (at 1100 m), there's probably not the growing conditions' history that more common cycads have. As I did some searching, hardiness and growth rates were all over the spectrum. I suspect that summer heat is one key factor to "pushing" cycad growth. How hot can you keep them? In pots, full sun on concrete, or surrounded by concrete or dark stone if in ground to soak up the heat.
Here's a bit I found on the climate of Panzhihua:
"Climate: Situated between the south subtropical and north temperate zones, the climate of Panzhihua is complex and varied with a longer summer. Its four seasons tend to blur, but there are clear wet and dry seasons. Generally, early June to October is the rainy season and November to May is the dry season. The hottest weather usually appears in May, and the temperature varies greatly between day and night." There wasn't any info on summer temps though.
Here's a comparison by one on-line supplier. Plant Delights Nursery is located in North Carolina, which would be colder than you in winter, but much warmer in summer:
Cycas panzhihuaensisSun to Light Shade Zone: 8-10, guessing 72" tall Origin: China
This rare cycad hails from China's southern Sichuan and northern Yunnan provinces, where it was discovered and named in 1979. Its natural habitat consists of dry, scrubby, wooded slopes where it grows in alkaline soils. Its location makes it one of the most cold hardy cycad species. In our trials so far, we have seen no leaf damage at 15° F [-9.5C]. When mature, the plant will develop a 6' tall trunk, topped with a ring of stiff "fronds," which emerge green when young but later change to glaucous. Despite reports of very rapid growth, I've seen dead snails move faster than these grow.
Cycas taitungensisSun to Part Sun Zone: 7b-10 120" tall Origin: Taiwan
In 2008, we were fortunate to visit the rocky, exposed hillsides in the Taitung Prefecture of southeastern Taiwan where this cycad calls home. Cycas taitungensis is similar in appearance to the popular house plant, C. revoluta. In 7-9 years (temperate climates), C. taitungensis forms a large rosette of stunning 5' long, dark green, plastic-like fronds circling the leg-sized trunk, which can eventually reach 10' tall. While the foliage will burn back at 20° F [-6.7C], all of our plants resprouted during their annual late spring flush, from 7°F [-13.9°C] in 2009. We recommend you establish these early in the season and mulch well until you have a robust trunk.
From another U.S. source (also North Carolina) selling small plants comes a slightly more scientific description:
"Fast growing for a Cycad, this species can reach a height of 2' in about 5 years, from seed. Our plants are now going on their fourth year and have several fronds and the beginnings of a central trunk."
So I know what cycad I want, thanks to you, but are you going to give it a try? There are some pretty good web sources for starting cycad seeds, and I've done it with
revoluta for fun (easy, but not exceptionally fast).
Let me know what you decide, please.
Monica
