Coral Tree vs Flame tree for Vista, CA?

[Bill Nun]

Could any socal experts make a recommendation on which tree I should choose? I'm in zone 10a, Vista, CA.   I want a real show stopper and really like the look of either a Delonix regia or a Erythrina caffra.  I've learned that the Regia may or may not bloom every year which kind of a bummer  and the caffra has some moth borer that is killing them in socal.   Maybe someone will have some additional suggestions.  The soil I have is heavy clay, nutrient rich.      Thanks very much.

[Silas_Sancona]

19 minutes ago, Bill Nun said:

Could any socal experts make a recommendation on which tree I should choose? I'm in zone 10a, Vista, CA.   I want a real show stopper and really like the look of either a Delonix regia or a Erythrina caffra.  I've learned that the Regia may or may not bloom every year which kind of a bummer  and the caffra has some moth borer that is killing them in socal.   Maybe someone will have some additional suggestions.  The soil I have is heavy clay, nutrient rich.      Thanks very much.

Tough call, esp. since both flower at different times.. If you have the space, could do both.. or, at least in the case of Coral Trees, ( Erythrina ) might research some of the others, like E. coralloides, X Syksii,  crista- gali..  E. flabelliformis, ( AZ native ), i think would do well there, esp. in the warmer parts of Vista. If they haven't been removed, remember seeing numerous E. humeana planted in a few spots along E. Bobier Dr., before you hit Vista Way. The last two will be smaller in size than the first 3 species though.  If you can find it for sale, E. latissima adds huge interesting leaves, on top of the usual red flowers.

As far as Delonix, might research species like D. decaryi, and D. Pumila..  They might flower a bit more reliably, but just a personal opinion.. White flowers rather than red however.. Interesting species regardless.  There are two more, D. elata, and D. leucantha ( tough to find ) worth researching also. Have the first two, looking for the others.

Moving to the area soon myself. Have some things i don't think have been tested much out there that will be interesting to see how they perform. 

[Mangosteen]

Two entirely different kinds of trees. You can grow and find Erythrina caffra easily. They have a nice one at the Home Depot. They are bulletproof, but not IMHO a showstopper. They are everywhere. On the other hand, where are you going to even find a good size Delonix regia? Vista is a great place to "try" one. They are by no means an easy grow and demand one of the best micro climates on your property. I grew mine from seed here in south Orange County just north of you. It was slow at first but after a few years, it took off. No flowers yet after about 8 years. Its about 12 feet tall now and the same wide.

[mnorell]

Delonix regia is a dicey plant anywhere but the low desert, but one that everyone wants to try...and many fail in the coastal zone of SoCal, but some have excellent results even in cooler coastal areas in just the right combination of circumstances. But it is a very finicky plant in terms of its seasonality and the textbook on how to get it to "do its thing" is that it wants a certain amount of heat overall (Florida! Palm Springs! Dubai! Madagascar!) and it really wants a warm, dry spring to set its buds before it leafs out in summer. That is usually impossible to provide in coastal SoCal because of the near-constant eddy as it really doesn't warm up until about the 4th of July. This is why it is spectacular in the Florida Keys on barren, hot, dry, rocky substrates with zero irrigation. And even in the frost-free areas of the low desert, they are often planted in wide grassy areas where they receive year-round irrigation, which spoils their flowering, reducing it to a smattering of occasional flowers all summer long, but never a really good show. If they would just shut off their irrigation from January to May, the trees would be spectacular in bloom, but the grass would die, too! (And we can't have that.) They are also sensitive to overhead lighting and must be planted in areas without any interference from such street-lighting or you will see no (or few) blooms. It is a picky baby and you will want to cut the thing down after a few years if it doesn't perform for you.

And there are many other gorgeous Erythrina from both hemispheres, and I will also second Erythrina latissima, which is really something that can stop you in your tracks. Beautiful leaves, bark and flowers. But you will probably have to grow it from seed (much is available on eBay). If you are concerned about the Erythrina twig-borer, which I believe has been very localized in its attacks so far, you might look to see if there are any resistant species. It is a New World moth, and so many of the New World Erythrinas may be more tolerant as compared to the African species. If indeed this is the case (I can't find any info confirming it, but it is a generally used assumption with such pests) you could try Erythrina poeppigiana, from Central America and northern South America, which is a real stunner...but it is more orange than red, and you will also have to grow it from seed (though it is very fast). 

Outside of those two genera, there are so many beautiful flowering trees you can use in the greater San Diego area, perhaps you should explore some of the other showy options you have available. Visit the San Diego Zoo and Balboa Park, Quail Gardens in Encinitas (I think they are now called San Diego Botanical Garden?) and you can also try the Arboretum in Arcadia and Huntington Gardens in San Marino, all have good collections of unusual flowering trees. 

One I would recommend is Cassia fistula, the Golden Shower Tree from India. It is spectacular yellow-flowering tropical tree and will bloom beautifully in SoCal particularly up against a hot south- or west-facing wall. It will also take a little frost now and then, which you may have to contend with in Vista depending on the situation of your property there. Some of the other Cassias have been flowered in SoCal (Cassia grandis, for example), and there are a number of Tabebuia that are feasible and quite spectacular but none are red.

If you have to have a red tree, you might look into Bombax ceiba. It is quite showy but more vertical than horizontal in form. Spathodea is an excellent choice but only if you are in a frost-free spot. They can easily be frozen back significantly or even killed by a good freeze.  Schotia brachypetala is a fairly showy red-flowered tree from Africa you might want to look up, as well. As I say, there are many and you can spend a lifetime studying them all! Good luck with whatever you choose.