Posted by Richard, TX on 8/6/2007, 11:31 pm, in reply to "Re: Just saw this post" The best place for eucs in South Texas is along the Rio Grande west of McAllen on up to the very best town Laredo, where there are a number of camaldulensis that did not freeze all the way to the ground in '83 or '89 and from what I understand barely suffered dieback at all in the '51 and '62 freezes. Carrizo Springs also has some interesting old eucs. Closer to the coast the warm winter nights prevent sufficient hardening and they generally freeze down to the ground in an extreme winter. There are lots of camaldulensis down here, the next most common species being citriodora (at least around Brownsville). There is a guy who owns a golf course between Donna and Pharr that has a number of species planted out, including camaldulensis, robusta, saligna, grandis (I think), sideroxylon rosea, and erythrocorys (surprising as it is not reported to be a good performer in climates with hot humid summers). He drills iron pellets into all of them at least once a year or he says they start to yellow. I think his soil is exceptionally bad for eucs there though. Probably my favorite down here is camaldulensis obtusa, it grows very well in Brownsville and has very attractive white bark with a pendulous crown. I've also seen it around Alice, Mission and the Gregory-Portland area. All appear to have frozen to the ground in '89. I have wanted to try ptychocarpa down here but have never gotten it past the seedling stage, it has damping off problems apparently. If it could take our soils it should be an excellent ornamental. In the past I've given people seed of several species to try here, and some have reported luck with trabutii, something like terminalis, tessellaris, pilligaensis and perhaps a couple of others. Populnea and melanophloia are high on the list of ones I want to try. I need to make a list of all the seed I have, I have packets of a lot of them, plus some melaleucas and other Australian myrtaceae. I have one amplifolia in the ground in Brownsville which is showing signs of chlorosis, as is a larger papuana right now (but an intertexta and blue microtheca from Arizona is fine). All the recent rain may be responsible. In San Antonio I also have camaldulensis Silverton, largiflorens, several forms of microtheca and a newly planted amplifolia from the U of Florida. There are a few microtheca in San Antonio but 99% of the eucs in town are camaldulensis, though I do know of one citriodora by Jefferson High School. In Austin microtheca is more common. The species from cooler climates (neglecta etc) have been complete failures for me, I think it's the heat, drought, alkalinity and cotton root rot that does them in. I think in South Texas there is a kind of bifurcated potential for eucs: one as shade/forestry trees and the other as smaller ornamentals. The more challenging use is for larger shade or forestry trees since it will take further breeding and weeding out to find clones that are well adapted to both the soil and snap freezes without dying back to very large wood (I have my eye on one cam clone in Brownsville that appears to have gone through '89 with its larger branches intact but need to work on trying to get it to throw basal shoots for rooting). A guy in New Mexico is also trying to improve the hardiness in camaldulensis. Some provenances such as the Flinders Ranges may be a little hardier (some are certainly pretty) Microtheca may have some potential but it seems if anything to be touchier than cam in snap freezes. There was a large trial of microtheca provenances north of San Luis Potosi in Mexico that may have been tested in the '97 freeze but it has been impossible to get access to the property they're on, the owner of the ranch refuses to even admit it exists. A very hard EARLY freeze in Arizona would be an ideal way of mass screening for microtheca. Further improved clones of amplifolia from Florida might have potential, especially if they could be grafted onto the salt/alkali tolerant forms of camaldulensis without losing most of their hardiness. Again, a hard freeze is needed over there for effective screening. All in all though Casuarina cunninghamiana probably has more potential for shade/forestry uses here, some provenances like Hartley and Bathhurst apparently have very good frost resistance and there are some individuals around S Texas and N Mexico that suffered little damage in the '80s (I have some seed of the Hartley form if you're interested in trying it). The other potential for eucs as small ornamentals should be easier - if they froze back it would not be a major project to remove the dead wood. Some of the desert corymbias or species from the northern parts of Australia have really good potential. They need to come from semiarid summer-rainfall regions on alkaline or at least alluvial nonacidic soils. Callistemon and Melaleuca are also good candidates for ornamental use, there are even a few C. vinimalis that survived '89 with their main trunks intact. Even a few of the nasty M. quinquenervia did not freeze all the way down. My favorite is the stunning M. argentea with its very silver leaves contrasting with the white papery bark. It seems to stay small here. Down here in S Texas the best tree in the myrtle family is the Tamaulipan form of Myrcianthes fragrans. It is native 90 miles S of the border and it comes up everywhere in the yard and has been hardy to the mid-teens in SA If you're ever down this way let me know, the Australian plants are a hobby that waxes and wanes with me, I don't have a large yard in South Texas so I'm a bit limited with trees (right now I'm focusing my time into tortur - errr TESTING - smaller subtropicals down here such as aloes and bromeliads. And palms as always). Australian plants have a lot of potential for down here, from the myrtles and acacias to the palms and cycads. The hardest part is finding hardy material, the woody plants all seem to have dormancy issues. Argentina is a much better place for more suitable material, even South Africa seems to be a better place for finding trees suitable for our area over the long term Richard
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Tom
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