Mandevilla plants are beautiful flowering vines that require a site less water than many similar tropical and sub-tropical species.
But, how often to water Mandevilla, exactly?
Mandevilla plants generally require an inch or so of water weekly. In hotter climates, Mandevilla benefits from two weekly waterings, rather than just one. The waxy coating on their leaves and their robust root systems enable the plant to store moisture for longer periods of time than other flowers.
Read on below and learn everything you need to know about how often to water Mandevilla!
Which Factor Affect Watering Mandevilla?
As with most blooming/flowering plants, there are numerous factors that affect the amount of water necessary to keep your Mandevilla healthy and thriving.
We discuss each of the most crucial of these factors in the following subsections:
The current growing season is, of course, one of the main factors to take into account before applying water to your Mandevilla’s soil.
Mandevilla requires watering in the late winter, spring, summer, and fall.
The plant doesn’t generally need watering over the coldest winter months.
Amount of Sunlight
The amount of sunlight that your Mandevilla receives is another big factor.
The more light that the plant receives, the less moisture it retains (thanks to increased evaporation rates, because of the sun).
In other words, the sunnier the location is, the more often the Mandevilla needs watering.
Amount of Air Flow
The amount of airflow around your Mandevilla is a critical factor that is often overlooked when it comes to watering.
However, the airflow indeed has a major effect on the plant’s moisture levels.
Mandevilla with plenty of air flowing around it dry out a bit faster, whereas the ones that have poor air flow stay wet longer and may develop root rot or other issues.
Plant Types of Mandevilla
There are approximately 200 individual species of Mandevilla, each one slightly different from the next. In some cases, one species may be thirstier than the next.
The biggest differences between various Mandevilla species are that some grow like long vines, while others grow like mounds of vines. Likewise, some take more or less water.
That’s why it’s important to do proper research on any of the Mandevilla flower species you are interested in planting.
A few of the most popular species of Mandevilla to grow at home include:
- Mandevilla Sanderi
- Brazilian Jasmin
- Mandevilla Splendens
- Mandevilla Laxa
- Alice Dupont Mandevilla
- Mandevilla Amabillis
- Mandevilla Brachysiphon
Phase of Growth (Including Seedling)
The phase of growth that your Mandevilla are currently in also affects the amount of water that you should provide them with.
Seedlings require much higher levels of moisture than mature Mandevilla.
The soil should be kept moist and warm for at least four weeks when you plant from seeds (meanings, you should water it a bit daily).
Mature Mandevilla plants should be phased down to just one to two watering sessions all week.
Plant in the Ground vs in the Container
Whether you plant your Mandevilla directly into the ground (in your garden, yard, or flower beds), or plant them in containers/raised beds also makes a significant difference in regards to watering requirements.
In the ground, the water you provide is spread out further and absorbed by a large number of species (plants, weeds, trees, shrubs, and grass, for starters).
In containers, your Mandevilla captures the majority of the water you provide to the soil.
In other words, Mandevilla in the ground needs to be watered a bit more thoroughly, to get the same effect as watering your Mandevilla in containers.
How Often to Water Mandevilla?
For the best results, water your mature Mandevilla just once or twice per week. Water them no more than once every 3 to 5 days, and no less than once every 5 to 10 days.
Mandevilla thrives when they are slightly moist all the time. That is not to say they enjoy being “wet” all the time because they do not.
There is a fine line between being soggy/wet, and moist. Mandevilla that are kept too wet may develop fungus, bacteria, or even the infamous root rot.
How Much Water Does Mandevilla Need?
Mandevilla requires around an inch or two of water weekly, which isn’t any more than the average plant.
Another way to put it is that Mandevilla needs approximately three to four inches of moisture surrounding their main root system/central stem.
In hot climates, that means you need to water the plant at least twice per week.
In cooler climates, you may get away with watering the plant just once every five to ten days.
How Do I Know When to Water My Mandevilla?
There are a few ways that you can tell your Mandevilla needs watering:
- The leaves are drooping
- The leaves are turning yellow
- The leaves are dropping
- The soil in the pot is dried out
- The ground is completely dry
To test the soil, simply stick your finger into the dirt (around two or three inches deep). If they are dry when you pull them out, your plant’s root system is dry too.
Alternatively, you can use a moisture meter to read the soil’s current state and deduce whether it needs more water at the current time or not.
Can You Overwater Mandevilla?
But, will too much water hurt Mandevilla? Yes! Too much water will most definitely set your Mandevilla back, healthwise.
The Mandevilla species has spectacular roots, which are excellent at storing all the water they need and then some.
When they are overwatered, it stresses them out. Too much overwatering may even lead to their death.
How do You Revive an Overwatering Mandevilla?
The best way to revive a Mandevilla you’ve been overwatering is to dig it up, carefully, and replant it.
The reason it needs transplanting is to reduce the amount of excessive moisture it’s been exposed to immediately.
When you move the plant into fresh dry dirt, even with its overwatered roots and a bit of soil, the excess moisture is quickly wicked up.
Give your overwatered and stressed-out Mandevilla anywhere from a few days to a few weeks in its new soil and it’ll return to its former glory.
How Do You Water Mandevillas?
Watering Mandevilla is as easy as one-two-three:
- Prepare a watering can, or turn on your irrigation system
- Apply water to the soil directly surrounding the central stem of each Mandevilla
- Avoid wetting the leaves and flower petals (avoid overhead watering)
Do your best to feed the water directly into the ground above the root zone, and avoid getting the plant wet.
If you do get the plant wet, it’s no big deal as long as you tap the central stem a few times and vibrate the water off.
When to Water Mandevilla?
There are two “best” times to water your Mandevilla; the early morning between 5 or 6 AM and 10 AM, and the evening, between 5 and 7 or 8 PM.
The reason the morning is the number one best time to water your Mandevilla is that there is less evaporation occurring then (before the sun is hot).
Before or after the sun is full in the sky, causing the earth’s temperature to increase, is the best time to water plants, period.
Watering Winterized Mandevilla
Wintering your Mandevilla plant includes cutting the water supply down drastically.
If your plants are outside in the ground, simply stop watering them once it’s freezing outside. Otherwise, reduce to watering just once per month.
In pots, reduce watering to just enough to keep the soil from being dry as a bone. Don’t increase watering until the spring when the plant shows new growth.