I am working in a mission in Dodoma, Tanzania, East Africa and we are trying to grow paulownia tomentosa trees for lumber/firewood/possibly cattle feed. I managed to sprout some from seeds back in November, and they grew fine until about the end of February. Since then (It's now the middle of May), they have simply ceased to produce new leaves or grow at all. There really is no winter here, just a rainy season and a dry season.(Its the dry season right now) So I don't see why they would be dormant or something like that. The leaves have not fallen off or died, but they have wrinkled. I have tried asking local people if maybe the problem is the soil, but it seems that this soil should be adequate, considering the information I have been able to gather online. The soil is very hard, but only when it dries out. If kept moist, it is fine. Should I try coppicing them? I have already tried reducing the amount of water they get, and will try to reduce it further, as I think I was over watering before. Can anyone help?? I am all out of ideas!
Paulownia tomentosa is a temperate climate tree; it is probably 'confused' by your lack of a winter, not getting the correct dormancy signals it requires to stop growth in autumn and then re-start growth in spring. Try something different that is adapted to a wet-dry season tropical climate, maybe something like Gmelina arborea or Leucaena leucocephala (though these may also be potentially invasive species).
Re: Paulownia trees not growing The Bermudagrass may be too competitive in terms of water and nitrates. If you can control it (spray) or at least remove it away from the trunks at least a meter they should do better. Note that Paulownia is highly sensitive to herbicide damage so only Fluazifop grass killer may be used. If you have a sandy soil nematodes can be a problem as well. http://rosecare1.stores.yahoo.net/fusiladeii.html
To add to Micheal's comment there are tropical and subtropical Paulownia species, P. taiwaniana, fortunei or elongata for example. http://www.toadgully.com.au/files/Data01.pdf http://www.toadgully.com.au/files/Tech01.pdf
Thanks for your advice everyone! I had sort of expected to hear the comment that they are really temperate climate trees, but I had thought maybe that wasn't the problem because it hadn't been that long yet- I'm not an expert, but I hadn't expected that to be a potential problem until closer to about a year after planting. Anyway, we will discuss the idea of possibly trying another variety or species. But in the meantime, saltcedar, you mentioned the possibility of nematodes being a problem. How do I tell and what might I be able to do about it?
There's no practical treatment for Nematodes(in tree crops). Mulch can help as can trap crops but ultimately you have to choose resistant species. If you find any nodules on the roots most likely nematodes are the culprit. The info in the pdf's above mention watering more often for the age trees you have. That plus mulch may get them moving again. Mulching seems to be a foreign concept to so many in agriculture it boggles the mind. See a permaculture website for the value of mulches. http://vimeo.com/moogaloop.swf?clip..._byline=1&show_portrait=0&color=&fullscreen=1
