When caring for the Alice Du Pont Mandevilla, it is important that you remember it is a tropical plant and will therefore require different care and maintenance steps. Tropical plants, when grown in the United States, require certain living conditions in order to thrive and establish themselves. Luckily, the Mandevilla vine is easier than most tropical plants to care for.
After it is grown and mature, it will only require weekly waterings. If you live in an arid environment that doesn't receive at least an inch of water per week, then you may need to water it more frequently. A good indicator to go by is whether or not the soil is moist to the touch; this is the level of moisture your soil needs to support a Mandevilla. It is suggested that you follow a watering schedule when the plant is in its infantile stages; this will allow it to grow an extensive root system, meaning you will have a healthier and happy plant.
When it comes to fertilizing, the Mandevilla vine will always benefit from a general purpose fertilizer. It should also be consistently exposed to at least 8 to 10 hours of sun each day. Be sure to not plant trees or other towering plants around Mandevilla, as it will grow poorly in the shade.
Because this plant grows very rapidly, it is suggested that you provide it with some form of support, such as a trellis or an arbor. This will prevent the plant from being exposed to soil-borne diseases as well as provide it with even and ample access to the sun. Mandevilla must also be pruned because of the lengths to which is can grow. Never prune during the spring or summer time, unless absolutely necessary. Instead, wait until the winter time. Pruning should be used as a means to control its size.