In this guide to Plumeria watering, I want to share some of the best tips I’ve picked up over the years. Some from other plumeria collectors, but most from good old fashioned trial and error.
Plumeria are incredibly easy to overwater, needing exact care depending on when and where you plant them, and to add even more confusion, watering plumeria cuttings is one of the most fraught propagation challenges for any gardener.
The risks are easy to avoid when you know how, so let us help you to avoid common mistakes when watering plumeria plants.
Plumeria’s natural water requirements
Plumeria, or the frangipani plant, are tropical plants that are naturalized in tropical regions, and most commonly associated with the islands around Hawaii (hence its title – the Hawaiian Lei Flower).
Their gorgeous flowers and fragrant blooms are carefully managed by these clever but needy plants, by constant self-management of water uptake in their natural environment, choosing to grow on rich, free-draining, soil.
In nature, they protect their seedlings from the full sun by dropping seeds under their mature foliage, which gives a parasol of dappled shade to keep seedlings from drying out and regulating their water at the same time.
As the young plants mature they begin to compete for water with their parents, and eventually take over, drawing in moisture from rainwater whenever it’s available.
Thanks to their tropical preferences they are incredibly drought-tolerant plants, meaning like any houseplant, or ornamental tropical, it’s far easier to kill them with kindness than with neglect.
In this guide we’ll be sharing guidance on when to water, how often to water, and what quantities to water plumeria, but let’s get stuck into the basics, and how often to water plumeria.
How often to water plumeria
For plumeria grown in a heated greenhouse, or indoors, there are two ways to water them.
Method one; water a little, once per week. Fertilizing every 2-4 weeks (or annually with a mulching feed).
Method two; water plumeria plants only when they dry out entirely. Either using water meters or a simple finger test, you must check for any moisture left in the top two inches of the soil. If the soil is at all moist, do not water.
When it dries out, drench the pot completely, until water runs right through the holes at the base of the pot. This way, you’re repeating its natural environment, and it’s by far my favorite way to water plumeria and everything else in my tropical collection.
But there are some subtle differences that should be noted between container-grown plumerias, outdoor plumerias, or watering indoor plumerias.
How to water Plumeria in containers
Growing plumeria in containers is the most sensible option for most plumeria parents.
Cultivated plumerias, grown either outdoors or indoors, are best grown in pots that match their root ball. This way you don’t allow the space to over saturate in soil that isn’t used for feeding.
When you are-pot your plumeria, pot on to a container no more than 1 inch wider than its root ball. Plumeria roots are slow-growing, so this will suffice for at least two years, but as much as four before you need to worry about potting on plumeria again.
Any soil without roots will hold water that can turn stagnant and encourage bacteria and fungal growth.
We’ll cover that in detail later though as it covers all situations.
How to water plumeria indoors
Indoor plumeria are 100% reliant on their gardeners for water. They have no access to rain, and therefore will only ever get water when you do it manually. I know it seems obvious, but even plants that can cope with drought need attention occasionally.
For indoor plumeria grown in full sun, they should be watered every 1-2 weeks with rainwater rather than tap water whenever the soil’s surface is dry. Spider mites thrive in these conditions. Where the soil is dry, but the top growth is plump and healthy, and they can travel easily across the dry floor, but feed voraciously on the well-watered growth.
Trial and error will guide you here, and you will make mistakes, to begin with. When you get used to your new plumeria plants in their new space, you’ll eventually just develop instincts for watering.
Tip: I advise growing them in a south-facing window, around 1.5-2m away from the window to prevent overheating in unnatural spaces
How to water plumeria grown outdoors
For plumeria grown outdoors anywhere north of the tropics, especially where rain is more common, and cooler winters are normal, you shouldn’t need to water them at all.
To help regulate plumeria water in the soil, make sure they are clear of weeds around their bases, and have at least 1 foot of space around the plant to avoid over-humidifying in spring, summer and fall.
How to tell if your plumeria is overwatered
Anaerobic soil is the most dangerous consequence of overwatering. If you make your own compost, you’ll be familiar with aeration, and how important it is to get air to every part of a compost heap, or in the case of plumerias, right into the root ball.
Roots, despite living underground, need good airflow. Even boggy plants like marsh marigold are specially adapted to produce their own oxygen to prevent roots from rotting.
When oxygen is in short supply, and moisture levels are stagnating, fungus can begin to grow, and roots cease to be able to process the nutrients they need to help foliage develop.
The first sign of overwatering (or bad drainage) is yellowing leaves, which will later become falling leaves.
If you begin to see yellow leaves, they are the result of the roots failing to feed the plant. They will soon start to look brown, or develop black tips, which might even look more like leaf burn (in some cases this is true, as leaf burn can occur as a contradictory effect of overwatering, where the roots fail, and acid levels in the soil shift too high in either direction causing burned looking plumeria foliage.
Signs a plumeria may have too little water
Plumeria with too little water will crisp up, but the process is relatively slow, and easy to recover from. Overwatered plumeria are at risk of root rot, which can be hard to fix, but under-watered plumeria are easy to revive by soaking the root ball, and resuming regular watering.
To avoid under watering, make sure you move your plumeria out of full sun, especially for indoor plumeria plants. While they enjoy full sun and high temperatures in their natural environment when grown indoors a combination of irregular watering and poor ventilation can cause drought to set in faster and more dramatically.
The most upsetting sign of under-watering though is in your plumeria flowers. Plumeria’s fragrant blooms are their biggest attraction, but they rely on nectar production to fill their house with that unforgettable scent, so when they begin to produce buds, begin watering once a week for plants in full or high sunlight.
Watering plumeria cuttings
Plumeria cuttings should only ever be watered with rainwater. Tap water is much too harsh for their delicate new roots, so if you plan on taking root cuttings for plumeria, make sure you have a proper water butt set up beforehand to properly harvest rainwater.
Obviously, a light free-draining soil is essential for plumeria cuttings, which will help with watering. While the soil should never dry out completely, overwatering is a huge risk in plumeria cuttings taken in soil, as the young roots aren’t adapted to acid, or resilient against small levels of bacteria and fungus.
Rooting Plumeria cuttings in water
To avoid your plumeria roots from rotting at the cutting stage, try plumeria cuttings in water.
Again, rainwater is essential, as tap water is far too harsh for your plumeria roots. What’s incredible about plumeria, like many other tropical house plants, is their adaptation for water rooting, where they will send out specially adapted roots for submersion, that are almost entirely immune to root rot, until you pot them on into soil.
When to stop watering plumeria
For mature plumeria grown indoors or outdoors, they should be brought into dormancy in winter. They will begin this process themselves when temperatures drop below 70Fnbut need to be protected from frost, and should be kept indoors over winter if temperatures are below 50F.
When you do this, stop watering them entirely until spring when their fresh young shoots appear as they begin the new growing season. At this point, you can begin watering them again but they should not be watered at all when the temperatures are below 50F outdoors (even if they are indoors).
Dormant plumeria cannot process water and it will almost definitely stagnate and rot the roots, either through bacterial or fungal infection.
Plumeria Watering FAQs
How do you water indoor Plumeria?
Water indoor plumeria every 1-2 weeks when the top two inches of soil have completely dried out. By watering plumeria this way you are recreating their natural habitat as closely as possible, and creating a comfortable environment where their roots are protected from rot.
Should you water Plumeria in winter?
No, you should never water plumeria in winter. Plumeria are tropical plants, and go dormant in the cold months, even if you grow them indoors as their flowering, and new growth is triggered annually by day length.
Can you overwater a plumeria?
It is incredibly easy to overwater plumeria. Plumeria are highly susceptible to root rot and need excellent drainage in their potting mix, so ensuring they are well-drained is just as important as managing their water correctly.
Should I water plumeria leaves?
Unless you have a fungal infection on your plumeria leaves or tips, you should avoid misting them as they can develop problems as a result of added humidity. If you need to apply fungicides, pesticides or foliar feeds, spray these in the afternoon when the sun is highest, so the leaves have more time to dry off.
Plumeria are exceptionally fussy plants, but they are also incredibly rewarding. There is simply nothing else in your home that will give you the same fragrance and beauty as a plumeria, so it’s well worth taking the time to get to know your plants and the watering regimes they need.
Thanks for reading, and staying up to date with us at Plumeria 101. We’ve been learning how to water plumeria in private collections for years now, so I’m glad to be able to share our best tips for watering plumeria.