Answer #1 ·
Brent Wilson's Answer · Hi Susan,
As long as the foliage looks healthy and dark green, and new growth is being produced, I would think that you're not doing anything wrong.
For the first time, I too planted a Yellow Mandevilla this spring. Planted it to grow up lattice on the side of my back deck. Like daylilies, the flowers don't last more than a day or so but it should continue to flower throughout the summer on new growth. I'd recommend fertilizing it once every 4 to 6 weeks with a good flower food or once every two weeks with a water-soluble fertilizer. This should keep the new growth and more flower buds coming. I'm thinking that the number of flowers produced will increase as summer comes along and nighttime temps will be warmer.
Brent)