Delonix regia, CA-style

[fastfeat]

2014 seems to be a good year for Delonix regia in SoCal. Here are some of the better ones, tho not all have been as good as in past years.

Fullerton Arboretum (older, lawn tree-- the younger slope tree isn't impressive):

Irwindale:

Indio (three separate trees):

Edited June 19, 2014 by fastfeat

[DoomsDave]

We've had a bad drought this year, and that's the reason for the bloom. There's one in La Habra that's blooming too, but nowhere near as impressive as the ones in your pictures, I suspect because it's in a lawn.

[fastfeat]

We've had a bad drought this year, and that's the reason for the bloom. There's one in La Habra that's blooming too, but nowhere near as impressive as the ones in your pictures, I suspect because it's in a lawn.

Actually, all five of these trees are in (over)irrigated turf as well, so I don't think that's completely it. Mild winters help, but doesn't explain the lack of flowers of the second Fullerton tree. I think it's more complicated than just water and temperature. I suspect that most can't support full flowering every year here as well.

[Xerarch]

Great trees, do these bloom at the same time as Jacaranda? I'll bet that would make a nice combination if so.

[Silas_Sancona]

Great pictures Fastfeat, Nice seeing west coast specimens in bloom. The Irwindale tree gets better looking with each yearly update. Indio trees are spectacular. Wonder how specimens in the Phoenix /Yuma area are doing.

As far as prime flowering conditions go, while warm and dry winter conditions are a big plus, I've been told age plays a big part in flowering. That and how long they have been in the ground. Extra spring rainfall this year didn't seem to bother and Interestingly, among several large trees a couple blocks from the house here, two that seem to have the best flower displays atm are located within feet of a large pond.

This year, many of the neighborhood Royal Poinciana started flowering mid way through the Jacaranda flowering cycle. Now, some Cassia Fistula, and one of the two commonly seen Peltophorum species ( looks like P. pterocarpum) I encounter around the neighborhood just started flowering. Wish they were all in the same yard instead of being spread half a block or more apart.

-Nathan-

[MattyB]

One of my little guys, plugging away.

[DoomsDave]

Matt, what's the palm to the right?

[Palms1984]

Those are terrific photos! I suspect the many Delonix regia trees in the Coachella Valley and throughout the Imperial Valley are blooming like crazy this year, also. I'm sure it's due to the lack of rain and the very warm to hot temps from this past winter, throughout Southern California.

The Royal Poinciana trees here in San Diego bloom well every year. However, I'm guessing this year the trees will be as spectacular as in 2009 (when they bloomed as well as the trees in South Florida and Hawaii).

[Xerarch]

Ok, so I know stress can induce a tree to bloom, like you guys are talking about the influence of the drought on blooms this year. But I keep wondering, if drought makes for better blooming, why does Delonix regia bloom so much better in Florida and Hawaii?

[DoomsDave]

Ok, so I know stress can induce a tree to bloom, like you guys are talking about the influence of the drought on blooms this year. But I keep wondering, if drought makes for better blooming, why does Delonix regia bloom so much better in Florida and Hawaii?

In Florida, it's dry in the winter. Here in California it's wet in the winter. (We hope.) This year it was very dry, though not record-breaking. I'll bet that Delonix blooms like crazy in Kona, which is relatively dry, and not worth diddly in Hilo, which is wetter than wet.

Comments, Hawaiians?

[LJG]

Like Ken said, these trees are growing in heavily irrigated grass yards. Doubt drought is such a huge factor some have been saying.

Ken, can I have your job? You just drive around and look at trees right?

[fastfeat]

FWIW, here is a pic, shot this AM, of the Placentia tree on Tafola St that was riotous last year. This year, well...

This tree is about a mile from the Fullerton trees.

[fastfeat]

Great trees, do these bloom at the same time as Jacaranda? I'll bet that would make a nice combination if so.

This year, seem to be a few weeks behind Jacs in coastal SoCal. If they were as consistent as Jacs, then yes, the contrast would be great.

[fastfeat]

Great pictures Fastfeat, Nice seeing west coast specimens in bloom. The Irwindale tree gets better looking with each yearly update. Indio trees are spectacular. Wonder how specimens in the Phoenix /Yuma area are doing.

As far as prime flowering conditions go, while warm and dry winter conditions are a big plus, I've been told age plays a big part in flowering. That and how long they have been in the ground. Extra spring rainfall this year didn't seem to bother and Interestingly, among several large trees a couple blocks from the house here, two that seem to have the best flower displays atm are located within feet of a large pond.

This year, many of the neighborhood Royal Poinciana started flowering mid way through the Jacaranda flowering cycle. Now, some Cassia Fistula, and one of the two commonly seen Peltophorum species ( looks like P. pterocarpum) I encounter around the neighborhood just started flowering. Wish they were all in the same yard instead of being spread half a block or more apart.

-Nathan-

People in SoFla say that they bloom best after particularly warm, dry winters. It wouldn't surprise me, but I've seen them outrageous following wet winters and springs too.

The first Indio tree is on Sage St off SR111. It's the only one of several similar sized and aged trees blooming well on the same block.

[fastfeat]

One of my little guys, plugging away.

He'll get there eventually. How old, Matt?

One thing about the Indio trees is that they're fast-growing. Homeowners were saying the biggest ones were only in the ground 10-12 years. LA Co, OC trees are much older.

[fastfeat]

Like Ken said, these trees are growing in heavily irrigated grass yards. Doubt drought is such a huge factor some have been saying.

Ken, can I have your job? You just drive around and look at trees right?

Len--

Well, I had a good amount of free time being in between jobs.

Actually got to tag along with someone who does a good amount of driving for his job helps too...

[MattyB]

Mine is about 5 years old. But I just got irrigation on it last year. The palm next to it is Parajubaea toralyi microcarpa. I'll probably cut the Delonix down. I've got another one in a better spot.

[mnorell]

Remember that Delonix will not bloom properly under bright street lighting. Screws up their photoperiod sensory mechanism. Look at the pix above and notice which trees bloom and which don't...

[Brian Bruning]

Delonix regia is from a monsoonal climate zone in Madagascar. Monsoonal is the opposite of Mediterranean. That is wet summer/dry winter. They do well enough in south Florida although they get some winter rains. If this tree gets too much winter moisture it is prone to not setting flowers. Every type of plant has hormonal triggers, some use day length, red vs blue light, wet vs dry, whatever. Many "tropical" fruit trees need a slight winter chill to set buds such as lychee. They are from south China and it gets down to 50F or so there. Plant them at sea level in Hawaii and they won't fruit. Mangos need a winter drought or they won't set buds or the buds will get mold and drop.

We are having a lousy cherry season up here $6/lb. Our winter was quite mild even inland in the Central Valley so they didn't set many flowers and when they did bloom it rained and the bees stayed home. No pollination = no fruit. So it is not just tropical plants that have certain cultural needs.

They do grow peaches, grapes, persimmons, blackberries and some apples in Costa Rica and Colombia but at altitudes where it gets chilly in "winter." So in such places a person can easily get many fruits from both the temperate climates and the tropics as they grow just short distances apart but at different altitudes.

My inlaws are from San Julian Jalisco in the so called heights of Jalisco (Las alturas de Jalisco) and the altitude is 2044mtrs so that's just over 8,000ft. It gets cold there in winter and a coconut or a mango would not have a snowflakes chance there. No snow as they have dry winters but it never gets really hot even in summer and frost every winter. They are at 21 degrees north - far south of the tropic of Cancer but certainly not tropical. It looks like Californias rolling hills, oaks and all.

In Costa Rica they call the April to November our "summer" wet season winter and the "winter" (November to April) summer. I guess since the population is largely derived from Spaniards and Italians and they were used to a mediterranean climate they just assumed that wet = winter and dry = summer.

[LJG]

Remember that Delonix will not bloom properly under bright street lighting. Screws up their photoperiod sensory mechanism. Look at the pix above and notice which trees bloom and which don't...

Plants under street lights do tend to go deciduous later but no amount of light changes the fact they will go deciduous. I don't think being planted under a street light has any bearing on this trees flowering. Even Ken said last year the same tree you are referring to bloomed "riotous".

[Gtlevine]

Still bother me. I had a huge trunking Delonix that was approaching flowering age, then the fires of 2007 took it out. I planted 2 more of the, but it will be several years before they get back to the size of the ones I lost.

[LJG]

Gary, do you turn off irrigation to them in winter?

[fastfeat]

Sorry, can't find last year's pics yet, but here's the Placentia tree about 10 years ago. Last year was very similar.

Street lights on this block one or two houses down haven't changed over the years, AFAIK. I don't think that's an issue here.

BTW, if someone wants to give me a bunch of money to research the blooming issues here, I'm all up for it. I'd just require a large frost-free parcel in Nor SD Co, one in Dade or Broward, maybe one in Hawaii somewhere too. Accepting all donations...

Edited June 20, 2014 by fastfeat

[Gtlevine]

Gary, do you turn off irrigation to them in winter?

I cut the water November 1st

[mnorell]

Remember that Delonix will not bloom properly under bright street lighting. Screws up their photoperiod sensory mechanism. Look at the pix above and notice which trees bloom and which don't...

Plants under street lights do tend to go deciduous later but no amount of light changes the fact they will go deciduous. I don't think being planted under a street light has any bearing on this trees flowering. Even Ken said last year the same tree you are referring to bloomed "riotous".

The issue with streetlights is well documented. It created a furor when a group of old and beloved Delonix stopped flowering in South Miami after the installation of street lighting above them. The lights were finally removed and the trees bloom once again. Some Gables or Cutler Bay residents on this forum hopefully can pitch in to corroborate as it was a big news item. You can google it and it should come up with the details.

[LJG]

Remember that Delonix will not bloom properly under bright street lighting. Screws up their photoperiod sensory mechanism. Look at the pix above and notice which trees bloom and which don't...

Plants under street lights do tend to go deciduous later but no amount of light changes the fact they will go deciduous. I don't think being planted under a street light has any bearing on this trees flowering. Even Ken said last year the same tree you are referring to bloomed "riotous".

The issue with streetlights is well documented. It created a furor when a group of old and beloved Delonix stopped flowering in South Miami after the installation of street lighting above them. The lights were finally removed and the trees bloom once again. Some Gables or Cutler Bay residents on this forum hopefully can pitch in to corroborate as it was a big news item. You can google it and it should come up with the details.

Where is it documented? I didn't find anything on Google. Just curious to read about it.

I know deciduous trees drop their leaves later under street lights, but I never heard of street lamps changing flowering patterns so drastically as you describe. Either way I won't be trying to grow this tree again

[mnorell]

The trees are on South Miami Avenue. The original article was in the Miami Herald on 29 May 2010, entitled "ROYAL POINCIANAS: An explosion of color returns high in the trees." You can search it on the Miami Herald site but they've moved it to pay archives, though you can see the beginning of the article. However, there was an editorial posted there last year: Poincianas bloom once again

But of course Delonix has many other problems in coastal Southern California to contend with, such as wet winters, cold nights year-round, frosts in many areas due to topography, etc. They have been tried since the nineteenth century there and have received a major "fail" grade overall. Here or there one may succeed inconsistently, even rarer with any consistency as the climate is so very marginal for them and small changes year-to-year will affect them. (Even in extreme south Florida there are good and bad years for the Poincianas due to small annual climate differences.) But in the southwest they are of course much more of a success story on the air-drained slopes of the Coachella Valley, Yuma, etc. where they revel in the sparse water, warm nights and overall desert heat. But if you can get one going near the coast, it's certainly worth it and a mark of distinction to be sure, even if you have to get an unusually warm and dry winter to get the full effect. Perhaps seed from those successful trees can be produced and new generations that are at least a little more cool-tolerant will be available for further trial. But I have a feeling you can only push it so far. It's similar to trying Jacaranda mimosaefolia in the Florida Keys. A bloom here and there but generally a fail-grade unless an oddball year produces favorable conditions.

[fastfeat]

2013 -- Placentia tree (Tafola St)

------------------------

2014 -- Placentia tree (following a milder, drier winter)

------------

I suspect that trees cannot produce large floral displays in consecutive years in CA (despite following even "better" winter conditions the second year) because the total amount of heat during the growing period here is inadequate to compensate for the stress of the prior year's display. Trees here leaf out later, grow more slowly, and stop growing earlier in the fall than those in Florida and elsewhere. I suspect that CA trees are so taxed after heavily blooming one year that several years of recovery are needed to repeat it.

IF all other requirements were typically met (as is the case in Miami and environs), then I would expect that a mild, dry winter there would positively increase flower production.

Worth observing and documenting blooms on these trees if CA gets, say, five or so nearly identical dry/mild winters to verify or disprove my theory. But I think there will be bigger problems for the state should that occur...

Edited June 23, 2014 by fastfeat

[fastfeat]

"Perhaps seed from those successful trees can be produced and new generations that are at least a little more cool-tolerant will be available for further trial."

I've yet to see a coastal CA tree (uncertain about desert trees) produce seed even when pods are produced. Night temperatures get too cool too fast to allow full seed development. This is a common issue with other tropicals (Cassia fistula. Cassia angolensis, Lagerstroemia speciosa come to mind) here. I suspect that someday, some viable seed will ripen here. Of course, that doesn't mean those progeny will necessarily have additional cold tolerance.

"It's similar to trying Jacaranda mimosaefolia in the Florida Keys. A bloom here and there but generally a fail-grade unless an oddball year produces favorable conditions."

Basically true, just in reverse. It's the lack of cool night temps that Jacaranda mimosifolia needs to set buds that make it virtually worthless south of Lake Okeechobee. Likely, heavy FL spring rainfall and limestone don't help.

[mnorell]

That's a really interesting theory about some sort of exhaustion in Delonix. Who knows? I also suspect that Delonix is very sensitive to the chilly, winter-like spring that exists in SoCal until the June Gloom finally abates. This year it has hardly existed and perhaps that is one reason for those beautiful displays. Again, even in the Florida Keys there is tremendous variation, where it be year to year or tree to tree. But the driest sites in the Keys, with the smallest, most flat-topped and apparently stressed specimens, are decidedly more spectacular than those that are either irrigated or have found groundwater. My own trees certainly show marked variation, both in size and in flowering behavior. I think it's because one has really tapped into the freshwater lens and the other hasn't.

Re: Jacaranda mimosaefolia, I would say it is the fault of nurseries who sell this species without regard for climate. It seems that it is always for sale at the HD in Marathon and Key West. And yet Edwin Menninger wrote of the "Jacaranda line" in Florida back in the '50s, perhaps earlier. And of course Fairchild, the Tropical Flowering Tree Society, and others have championed the more tropical Jacaranda species (e.g., J. cuspidifolia) that bloom extravagantly in the climate of South Florida and the Keys. Sad to see that situation. I must say, though, that I've never seen a J. mimosaefolia that looks stressed from limestone in the Keys. They generally have a decent appearance aside from their sparse flowering behavior...

[Palms1984]

Here's the younger tree at Fullerton Arboretum It was blooming; however, it's so crowded with other shrubs and trees it's difficult to photograph. Photo taken June 28, 2014.

[DoomsDave]

Here's the Delonix in La Habra.

[_Keith]

Spectacular tree. I only wish I could grow them.