King palm as a canary for Dypsis?

[Phoenikakias]

If I am able to grow outdoors an Archontophoenix alexandrae (at least for some decades long), what Dypsis spp are also suitable for my climate? King palm should be considered as the border sp for my climate's capacity.

[BS Man about Palms]

I think that's a reasonable test. The biggest thing which I have espoused before is related to heeled Dypsis. They are VERY slow to develop a healthy root system and thus are CRITICAL to drainage. 
As I have noted elsewhere, if you have great drainage, almost no issue, but if drainage is a potential issue, plant high and mound the soil up. If too much water, it will shed the water off. If needs more, add more.

[Ben in Norcal]

In general, not a great barometer at least in my climate...all in the Archontophoenix genus grow well here, but few of the Dypsis.

If you can grow kings, Dypsis decipiens, decaryii, and anything in the baronii/onilahensis complex are good bets.  The decaryii/leptochelios hybrid is also a winner here.  I am experimenting with D. heteromorpha as well.

Most if not all other Dypsis melt in my climate - not due to absolute lows (never under 30F) but due to persistent damp and cool in the winter.

[Darold Petty]

I have an adult Archontophoenix cunninghamiana 'Illawara',  The Dypsis which grow for me are D. ambositrae, and D. baronii.  D. lanceolata is possible, but not yet conclusive.

[Josue Diaz]

Dypsis leptocheilos has endured two winters outdoors in pots in Fresno with minor spotting (similar climate to Ben's in Clayton, except with significantly more heat in summer.) I planted a 4-inch prestoniana from Hawaii around the same time. That one's been in the ground this whole time, and while it hasn't grown much, it also hasn't had any issues with our cold. My soil is very sandy though, so drainage is very sharp where I live. 

[Ben in Norcal]

10 minutes ago, Darold Petty said:

I have an adult Archontophoenix cunninghamiana 'Illawara',  The Dypsis which grow for me are D. ambositrae, and D. baronii.  D. lanceolata is possible, but not yet conclusive.

Ah yes - I forgot D. ambositrae as well, and I have like 15 of them!  LOL!

[Tracy]

2 hours ago, Phoenikakias said:

If I am able to grow outdoors an Archontophoenix alexandrae (at least for some decades long), what Dypsis spp are also suitable for my climate? King palm should be considered as the border sp for my climate's capacity.

I was reading through the diversity of responses you received.  It will depend on whether absolute cold, extended cool and/or your summer highs are your climate's Achilles heel.  The combination of those will all determine which species will survive along with your Archontophoenix alexandrae.  In my climate it isn't the absolute coldest nights that are the problem, instead it is the times of extended cool during the winter that some species don't like.  Since many of the heeled solitary species tend to be slower, experimenting with one or more of the clumping species might be your next "canary" for growing other more challenging species.  At least try one or more of the clumping ones simultaneous with any of the large solitary species.  While slow to get going, the most tolerant of the large heeled Dypsis are probably decipiens (heat and excellent drainage) and prestoniana. 

In my climate I would recommend Dypsis onilahensis and heteromorpha as probably the most tolerant of highs and lows, without showing leaf burn.  On the opposite end of the scale are cabadaee, mayotte, lutescens, pembana and lanceolata (in increasing tolerance order).  The latter ones tend to show more leaf tip burn and spotting with extremes of heat and cold for me, while onilahensis and heteromorpha will almost always hold more good looking leaves which fall off on their own. 

Ben mentioned Dypsis ambositrae, which is somewhat variable.  I remember seeing a number of different specimens that Hilo Jason was growing in his Fallbrook garden several years ago.   Some faster than others, some more tolerant of sun.  I have experienced the same with the two I have in my garden.  So be aware if you try this species that there may be a couple of slightly different plants grown as Dypsis ambositrae which may appreciate more or less sun and have different growth rates. My slower one is showing more of a saxophone growth habitp from it's heel while the other seems to be more upright and appreciate a full sun position.  Good luck with whatever you select and share your results!

[doubravsky]

This is an interesting conversation. I'll add my two cents from inland SoCal.... summer highs in the 110 (43-45 Celsius) range...  winter lows generally around 32 (0 Celsius) , although in some years down to as low as 28 (-2 Celsius) for a night or two. 

Archontophoenix- Cunninghamia are pretty bulletproof. I've lost unprotected Alexandrae and Purpurea during the winter. Protected success with Maxima and Purpurea, Illawara and Beatricii. 

Dypsis- I've lost Carlsmithii, several Decipiens, Heteromorpha, Slick Willy.  Bulletproof seem to be Baronii, Onilahensis, Ambositrae, Pembana, Lutescens. Protected success with Leptocheilos, some Hybrids, and one Decipiens (out of 5-6 I've tried). Hoping for success with Prestoniana, Lafamazanga, Hovomantsira, Pilulifera, and a few others....... 

[konarikcy]

I agree, if you are growing Alexanders in Greece, you must be somewhere where you dont get continual temps near zero in winter. I killed 3 Alexanders during prolonged damp winters near zero. Climate change may change that as our winters the past 2 yrs have been milder. I haven't had to rush outside and wrap trees up in a panic. I have 14 cumminhamianas or hybrids  I think growing happily with little winter (or summer of 46oC burn). Dypsis leptocheilos should certainly survived. These are some of my archontophoenix which although not alexanders have not yet been identified. Any suggestions. They are 3 years old and growing at a phenomenal rate.

[tim_brissy_13]

Archontophoenix are pretty much bulletproof here, but we have long, cool winters so only a handful of Dypsis are proven winners. D decipiens, baronii and onilahensis are the most reliable. D ambositrae and albofarinosa have no real issues either other than being extremely slow. There are a few D decaryi around town getting quite large, but most don’t look the best coming out of winter. I’ve only ever seen one D lutescens do well, most look really ordinary but usually survive for a while. I have a D leptocheilos that was going ok at my old house but developed some root rot after transplanting and looks like it is now on it’s last legs in its new location. 
 

I’ve also had good luck with D arenarum and D cabadae x madagascariensis. Ive got a few more I’m experimenting with but only less than a year in the ground for D pembana x madagascariensis, prestoniana, pilulifera, madagascariensis, lanceolata and psammophila. 
 

Some that haven’t done so well: D carlsmithii, D pembana, D dark mealybug, D leucomalla and D robusta. They survive for a few winters but don’t get enough heat to grow. D Scottiana was a complete wimp and didn’t last a winter for me. 

Edited October 16, 2020 by tim_brissy_13

[Phoenikakias]

I know of one instance of Lanceolata growing in Italy (the peninsula not Sicily or Sardinia), which has also bloomed this year for the first time but soil is very sandy. Further I have managed to keep alive in my garden a Dypsis lutescens but it does not look really well. Two Dypsis plumosa (from seeds kindly gifted by DB) keep growing bigger in my cold frame. This is so far my positive experience with the genus.