Frangipani not Flowering (Australian Guide)

You have a gorgeous frangipani growing in your garden and each year, you wait eagerly for those sweet-smelling flowers to grow.

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Once spring comes, you check your frangipani every few days to see those beautiful blossoms starting to emerge.

But, all you see is green growth and no flower buds. So, why is your frangipani not flowering?

There are a few reasons for frangipanis to not flower. Mainly this can be due to insufficient sunlight, lack of fertiliser, incorrect pruning or a problem with pests. Let’s discuss these in more detail.

Insufficient sunlight

For frangipanis (also known as Plumeria) to bloom prolifically, they need at least six to eight hours of bright sunlight each and every day.

This can be an issue if your frangipani is growing near large trees, or up against a wall, and only receives partial sun or is shaded for most of the day. In this case, you either have to move your frangipani or prune back the larger trees so that it gets a lot more bright light.

If your frangipani is growing in a pot, it should be fairly easy to move it around to a sunnier spot. You can even move it multiple times a day to take advantage of the sunlight. If you do this, you should be rewarded for all your effort with a multitude of fresh new blooms.

Lack of fertiliser

Many people believe that frangipanis don’t have to be fertilised, but this is just not the case.

Like all plants, frangipanis need a good dose of nutrients to grow to their full potential and produce plenty of sweetly fragrant blooms.

Here’s what you need to know about fertilising your frangipanis:

  • Fertilise in spring and summer to maximise your chances of a blooming frangipani.
  • Use a balanced organic fertiliser or something like rose plant food.
  • Check the label to ensure that the fertiliser has fairly equal proportions of nitrogen, phosphorus and potassium. This is written on the label as N:P:K or a series of numbers like 10:10:10 or 10:7:9. 
  • Avoid using a fertiliser that is too high in nitrogen as this will promote plenty of green growth but no blooms. Frangipanis also need phosphorus and potassium to flower.
  • You can use liquid fertiliser or a slow-release granular fertiliser.

Incorrect pruning

It’s important to note that frangipanis will only flower on older wood. This means that the stems need to be at least two years old before they will produce flowers.

Therefore, avoid pruning your frangipani branches too heavily in autumn or winter. You want to ensure that there are older stems that you leave alone and don’t cut back at all. 

You see, when you cut back a stem, new growth will happen from where the cut is made. This is great for encouraging a bushier plant, but these new stems won’t flower in the spring. You’ll have to wait another year for these to produce blooms.

So, when it comes to pruning, only cut back enough growth to keep your plant in shape and leave some of those older stems alone if you want blooms the following spring.

Insect pests can damage emerging flower buds

Although frangipanis are fairly hardy and don’t have too many problems with pests and diseases, they can still be susceptible to an attack from sap sucking insects such as aphids, thrips and mealybugs.

These annoying pests sap the juices from the plant and easily damage emerging flower buds, leaving you with no blossoms.

Here’s how to check if your frangipani has a pest problem and what to do about it:

  • Aphids. These are tiny green insects that congregate in masses on the new growth. They’re fairly easy to spot. If you see these on your frangipani, you can either hose them off with a strong spray of water or apply an organic insecticide such as neem oil mixed with water.
  • Thrips. These are tiny black insects that suck the sap out of your plant. You can treat them with a solution of neem oil mixed with water. The oil adheres to the insects and suffocates them.
  • Mealybugs. These are small white insects that look almost like little bits of cotton wool. They’ll be more visible on the undersides of leaves or along the stems. You might also see a sticky black residue on your plant that attracts ants. You can treat these with an insecticidal spray using neem oil and water. If there are only a few mealybugs on your plant, you can also spot treat them with a cotton bud dipped in isopropyl alcohol.

FAQs

What is the best fertiliser for frangipanis?

Balanced organic liquid fertilisers are good for feeding frangipanis. You can also use a granular or slow-release fertiliser designed for roses or other flowering plants. Seasol can help to stimulate plant growth and enables the roots to take up nutrients in the soil.

How do you promote frangipani flowers?

Make sure your plant gets plenty of sunlight and feed with a balanced fertiliser in spring and summer.

What is frangipani rust?

Frangipani rust is a fungal disease that appears as a rust-coloured powder and bumps on the underside of frangipani leaves. The disease spreads by spores being picked up by the wind and usually occurs after heavy rain and in hot conditions.

Photo of author

Annette Hird

Annette Hird has an Associate Diploma of Applied Science in Horticulture. She has worked in a variety of production nurseries, primarily as a propagator. She also had the responsibility of a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.