PlantFiles: Golden Trumpet, Yellow Allamanda
Allamanda cathartica 'Hendersonii'

Gorgeous when I was in Puerto Rico .. this plant / bush is all over the place in the top end resorts, pool side etc in the landscape. In west central florida it freezes out and comes back in May if it doesn't die - mulch heavy for winter frosts / uncover in April. Water but excessive water cuases yellow leaves and then leaves fall off - same with fertilizer. Diluted 20-20-20 OK but not granual nor weed & feed for lawns.
Partial shade OK too. If it does well in one location great, if not move it around till you find a place, then plant it and add to it. Not every spot is great for allamanda.

My original Allamanda came from cuttings from a plant which was over 12 feet tall. I kept mine trimmed to bush size, in full sun. It needs to have protection from freezes in the winter (heavy mulch helps), as mine eventually died.

It is a beautiful plant. The Brown Bud Allamanda has larger flowers than the other varieties. Spacing can be whatever you prune it to. I have one which is 5 feet diameter and 4 feet tall, which is pruned 2-3 times per summer.