Ask Mr. Smarty Plants

We certainly believe that Tecoma stans (yellow trumpetbush) can survive transplanting, and that it will flourish under more sunlight than yours are getting now. 

The first thing to do is choose your time.  They should be transplanted (as should all woody plants) during the period of dormancy from about November to February, in this part of Texas. First, trim them down considerably. Some references we have seen have said they can be trimmed to the ground if they have been affected by frost, and will come back. We wouldn't advise trimming them back that far, but certainly a good portion of the top can be taken off. This will relieve the strain on the roots when they are moved, making it easier for the roots to get moisture and nutrients out to the remaining branches on the shrub. Since you have time before you will be making the move, you might spend some of it preparing the hole. Yellow Bells are very tough natives, and can take lots of different soils and are drought resistant. But any plant will do better with a little soil doctoring, especially in the area of drainage. This is a desert plant, and a heavy clay soil that holds moisture around the roots is not going to help the plant at all. Try digging out your hole and mixing in some organic material such as leaf mould or compost into the soil and returning it to the ground. Then mulch over the space with a shredded hardwood mulch. When you are ready to transplant the Tecoma stans, take out as large a root ball as you can handle, damaging as few roots as possible. Get it back into your prepared hole as quickly as possible, trying not to let the roots dry out. Return the prepared soil to the hole, and, again, mulch. The mulch will help to hold in moisture, protect the roots from heat and cold and, as it decomposes, add more organic material to improve the texture of the soil. Stick a hose down into this softened earth, and let the water dribble very slowly until you can see water on the surface. This should be done about twice a week, more often if the weather is dry and hot, until the shrub appears well established and is putting on new growth.

Tecoma stans

Tecoma stans

Tecoma stans

Tecoma stans