September 14, 2023
The Searles Gardening Team
Summertime brings the sweet smell of frangipani in the air. It is hard not to have a frangipani growing in your garden.
The frangipani in this article is the Plumeria, a thick-branched tree that has a milky sap and is deciduous with a gorgeous, aromatic flower. Many think of the Native frangipani (Hymenosporum flavum), which is vastly different. Wikipedia states "The genus Plumeria is named in honour of 17th-century French botanist and Catholic monk Charles Plumier, who travelled to the New World documenting many plant and animal species. Plumeria is also used as a common name, especially in horticultural circles.
The name "frangipani" comes from a fictional 16th-century marquis of the noble Frangipani family in Italy, who created a synthetic plumeria-like perfume. Common names for plants in the genus vary widely according to region, variety, and whim, but frangipani or variations on that theme are the most common."
Frangipanis are generally chosen for their flower colour, so many gardeners wait to buy them in their flowering season. Be aware of the common name of evergreen frangipani. For most of Australia, they are deciduous trees, so don't choose your tree thinking some hold their leaves all year round. When it comes to the types of frangipanis plants, they generally fall into three types.
The riot of colour in flowering frangipani is generally attributed to Plumeria acutifolia, synonymous with Plumeria rubra, an iconic tree that can grow up to 10m. A slow grower with pointed dull green leaves, the acute angle of the tip refers to its Latin name acutifolia (acute=shape angle and folia=leaves). Characteristic sweet perfume flowers also come in a massive range from dark red, apricot, pink and, of course, white.
The classic white frangipani is Plumeria obtusa, the name refers to the varieties with the rounded end leaf. Sometimes referred to as the Singapore frangipani or evergreen frangipani, the Latin name obtuse refers to the end of the leaf and petals, with their obtuse angel, which means it is greater than 90 degrees and less than 180 degrees. It is a slightly smaller tree under 8m but still extremely slow growing. Their leaves are also a deeper glossy green than Plumeria acutifolia's, and only limited colours are available in the range.
Both Plumeria acutifolia and Plumeria obtuse have dwarf varieties, but when wanting a smaller, hardy, and fast-growing plant, you can't go past Plumeria pudica. It is sometimes called the Everlasting or hammerhead frangipani and can reach up to 5m. Depending on the situation, this variety tends to keep more leaves during winter. Its growth is relatively rapid and can be planted for screens and flowers over a prolonged period in warmer regions. The shape of the leaves adds notoriety as well.
Frangipani enjoy a full sun position and most well draining soils. There are a few issues that they are prone to. Overwatering or boggy soil or mulch touching their trunks can lead to fungal problems and rot. Be aware if a stem feels spongy, this is the first sign of rot and can spread throughout the plant and kill it. Early treatment with Searles Root Rot can assist with this, but it is imperative to find the cause of the rot and address it. Frosts can harm them, and they must be protected when young.
The main issue that frangipani owners now face is Frangipanni rust. A bright yellow rust pustule that forms mainly on the underside of the leaves. This disease came into Australia over a decade ago and has spread south along the east coast. It is a difficult one to address, but following strict hygiene protocols helps reduce risk. Remove, bag and bin any infected leaves, especially those that have fallen to the ground. Never put these remains in the compost, as the spores can stay alive and reinfect the garden. Clean tools after using them on infected plants. Spray fungicides registered to kill rust regularly, including the top and bottom of the leaves, stems, and the ground under the trees. Use alternating different sprays, so the disease does not develop an immunity to one spray type. Searles Trifend can be used as one spray. Continue alternating sprays until under control. It will come back, and no treatment will stop it.
Fertilising is easy with frangipanis in the garden, as Searles has Hibiscus and Bougainvillea Fertiliser designed to promote blooms. Apply every three weeks and water in well from October to June, their general flowering period. For frangipani in pots, apply Searles Recharge Fruit and Flower every six months or fortnightly with Searles Flourish Flowers & Foliage.
A simple plant to propagate, cut off a piece over 30cm long and leave it in a dry, sunny position for a week or so, then plant it into a well-drained mix such as Searles Propagating Mix or Searles Seed Raising Mix. Make sure to support the cutting; it will root over the next few weeks to a month. Once it has roots, it can be planted or potted out. Use Searles Seamax Organic Fertiliser fortnightly as a gentle nutrient nudge to get it going. Refrain from using a more potent fertiliser until it has developed several leaves, and make sure there is never water left in saucers, or rot can easily take hold.