An incredibly delightful beauty that’s also extremely toxic
NERIUM oleander is a Southeast Asian shrub that belongs to the dogbane family of Apocynaceae. Some references say that the plant originated in the Mediterranean region. Its taxonomic name was originally assigned by Linnaeus in 1763. Nerium is widely cultivated for its beautiful flowers and mainly used for landscaping uses.
Although incredibly beautiful, there is a drawback with having this in your home garden as the shrub is also one of the most poisonous garden plants. However, the flowers will add much beauty to the garden and as long as handled with care, nerium will reward the home gardener too.
Background
Nerium oleander’s leaves are dark green, narrow, lanceolate, long, and less broad. The flowers grow in clusters at the end of each branch with a fivelobed corolla.
It can reach a height of 12 feet. The plant should flower within the first year of growth and is likely to last for many more years to come.
Nerium’s flowers can be single or double forms with masses of pink, rose, white, crimson, and purple. There are also some with variegated forms. They are very ‘showerproof’ and often fragrant. This makes the flowers very attractive in many contexts. The plant produces a fruit that is a long narrow pair of follicles that split open at maturity to release numerous downy seeds. The flowers require insects to visit in order to set the seeds. Both seeds and cuttings are used for propagation.
Nerium oleander requires good sunlight, warmth, and plenty of water to flower freely. It is a vigorous grower in a suitable climate and is tolerant of poor soils, intense heat, salt sprays, and sustained drought.
There are over 400 known cultivars and many varieties such as Hawaii and Turner’s Carnival are multi-coloured with striped corollas. Several dwarf varieties have also been developed. They offer more compact forms and sizes, which make them ideal for small spaces. In fact, this flower is very much appreciated in many countries and useful for other industrial purposes besides landscaping.
The ornamental uses extend to roadsides and screen plantings as hedges. It can also be established in pots or tubs for patios and terraces.
Growing tips
Water is critical for flowering, however if the leaves start to show signs of yellowing, it could mean that the plant has gotten too much water. Once planted, the plant does not require any routine fertiliser regime.
Pinch out the tips of young stems to reduce legginess and encourage the plant to branch out.
The plant is actually very easy to care for. As such it is popular for roadside landscape design.
Pest and diseases
Despite the highly toxic content of Nerium plants, there is a bacterial disease called oleander leaf scorch, which is a serious threat to the shrub overseas. The culprit is Xylella fastidiosa, which will spread via insects feeding on the leaves. This causes dieback due to a scorching effect. To treat, it is best to prune the affected segments to slow down the spread.
Caterpillar damage is also known. They will defoliate the oleander and give the leaves a skeletal appearance if not controlled. Caterpillars can be stopped using a Bacillus thuringiensis or Bt spray. This natural bacterium does not pose a risk to beneficial insects or human contact.
A warning
The very first thing we should remember is that we need to avoid growing oleanders in areas where children and pets play. All parts of the shrub are poisonous. Note that even the smoke from burning oleander debris is toxic too.
Ingesting even a small amount of the foliage, flowers, or shoots from this plant can be fatal. Some contact with the foliage and flowers can cause severe skin irritations and allergic reactions as well. Always wear long sleeves and gloves when working with this shrub.
On a final note, readers should not venture into planting this shrub unless you are fully aware of how toxic the plant can be so that extra special care is taken while handling it.
Send me an email if you have questions, comments, or suggestions. Happy gardening.