Conocarpus erectus v. sericeus

[mnorell]

I was in New Orleans today at HD and to my great shock they had a supply of nice 3gal silver Conocarpus erectus v. sericeus (Silver Buttonwood). I'm usually not a big silver-foliage person, but Bismarckia and this shrub/tree are major exceptions, I always love seeing these driving through Florida, particularly the Keys, where this one (like Bismarckia) is so silver as to appear white.

I bought one of these beauties and now face the issues surrounding its culture in my (I'm sure) somewhat inhospitable 9a Natchez climate. Can anyone illuminate in regards to cold-tolerance and behavior after freezes, as well as its tolerance of more acid soils than the coral beds of the Keys? Also anything in regards to tolerance of perhaps light shade (in case keeping it under slight canopy might increase its surival rate)...obviously these grow right out in the strong tropical sun so I know they love full exposure if they can get it.

I'm hoping someone in North Florida or other 8b/9a Gulf areas has tried successfully or otherwise to trial this beauty...perhaps as a returning shrub after freezes. Comments anyone???

[jayfro6]

I've heard they are slow-growing, but they are a beautiful tree. I only see them planted in coastal areas like Ft. Lauderdale. The regular green buttonwood seems to be limited to zone 10a--the farthest north I remember seeing them is in a tidal swamp at Apollo Beach south of Tampa.

[SunnyFl]

  jayfro6 said:

I've heard they are slow-growing, but they are a beautiful tree. I only see them planted in coastal areas like Ft. Lauderdale. The regular green buttonwood seems to be limited to zone 10a--the farthest north I remember seeing them is in a tidal swamp at Apollo Beach south of Tampa.

The problem with conocarpus seems to be that, away from the coast, it can be prone to sooty mold. But this isn't the case near the salty air of the coast. Or so I've heard.

I imagine the sooty mold could be treated. Silver conocarpus is very striking, whether grown as a tree or trimmed as a hedge. I once saw it hedge trimmed, with selloum out in front - that was amazing.

[Jerry@TreeZoo]

I can't tell you much about buttonwood's cold tolerance but I can tell you a few other things about it.

There are two main forms, the "silver" and the "green". The silver leaves are actually green, but have tiny silver hairs on them, the green shows through a little when they are wet. There are gradations between the wild silver and green forms, they just don't make it into the trade much. As a rule, the silver is more "rangey" and spread out and the green more upright. The green usually makes a larger tree. Most of the driftwood you find on beaches in SoFla and the Keys are buttonwood. "Momba" with larger, darker green leaves and "Card Sound" with unusual narrow leaves are two varieties of the green form. I have seen a silver variety called "Silver Sheen" advertised.

While the silver demands full sun (and will thin out badly without a few hours daily) the green is more able to handle light shade. They make decent hedges running North and South (in full sun) but can get leggy if their tops are wider than their bottoms. East , West hedges can thin out on the North side, especially the bottoms. They are very salt tolerant and have a pair of glands at the base of their leaves that will exude excess salt in their system. These same glands are responsible for the sooty mold forming noticably on the silver form. They can tolerate wet feet but don't like persistant flooded conditions. (Think of daily tidal flows, not swamp land) They are relatively drought tolerant when established. They thrive in almost any SoFla soil; marl, rocky, sandy, muck etc. The growth rate in good conditions in SoFla is very fast.

The wood is very hard and was actually used for making buttons. Old trees are very picturesque because of their knarly growth habit and ropey trunk. Dead wood is often used for mounting bromos and for large bird perches.

Jerry

[mnorell]

Thanks everyone for all that great background and info. Indeed I think this would make a great foil for the lush green of things like selloum, Heliconia, gingers, etc. I'll just plant it out in full sun and mound/mulch it next winter for a trial. I certainly don't expect it to be hardy in my 9a climate, but it would be nice if it had fast growth and root-hardiness to pull it back up into a respectable specimen each year. We have plenty of heat and sun here to make it go, that's for sure!

[bahia]

I've seen this planted out as a tree/hedge in the subtropical desert climate of Riyadh, Saudi Arabia, where it can and does occasionally freeze, although freezes are of short duration and days quickly warm back up. It has gotten down to 28F there, so the Buttonwood is hardy in that sense, but probably doesn't do as well with extended cold or freezes followed by long periods of cool near freezing weather. It is not seen here in California, or at least northern California, and was valued in Riyadh because it was so fast growing, and broadly tolerant of extreme heat and winds and saline soils. The green leaved form struck me as great visual substitute for Lombardy Poplars, they both have similar growth habit.

[fastfeat]

The farthest north I recall seeing this is in Largo, FL in a homeowner's swale. Not very large, but it had been through a few winters. Definitely seems to gain vigor as one heads south--much better looking in South Dade and Keys than Palm Beach Co, IMHO. That said, Michael, you might try it, but keep your expectations realistic.

Probably not possible in coastal SoCal (cold winter soil), but with that info about it in Saudi Arabia, it might be worth trying in Phoenix or Palm Springs, if there's any water left...

[Eric in Orlando]

I see it occasionally planted around here but no big specimens. In the past ours has gotten damaged below 28F. Years ago I grew one at an old house I was renting. It was in the open backyard which was a real cold pocket. It was killed back after a night at 26F but never grew back from the roots.

[mnorell]

Thanks, Eric. Very useful info, especially in that it didn't return from the roots. It's already planted here in full sun and I'll enjoy it this season, bank it with sand for next winter, and await the results...