Are you looking for a fast-growing, neat, and dense plant for screening or hedging? Pittosporum might just be what you’re looking for, with a variety of sizes and foliage colors available. Read on to learn more about these plants and how to grow and care for them.
What Is A Pittosporum?
Pittosporums are shrubs or trees of the Pittosporaceae family. There are around 200 species, which are native to Southern Africa, Australia, New Zealand, and Eastern Asia.
The word Pittosporum basically means sticky seed in Greek. The word is derived from the Greek word for pitch(pitta) which is a substance similar to glue, and seed (spora). These ornamental evergreen shrubs and trees have a neat and tidy growth form and are often called cheesewoods.
Wild species vary greatly in size and grow anywhere from 6-100ft (2-30m) in height, but fortunately for us, several horticultural varieties have been developed to grow much smaller.
These plants generally occur in mild climates, where they grow in areas that receive good rainfall and warm conditions without severe frost. Some species are tougher than others and do well in exposed, coastal areas where they may be in contact with salt spray.
Pittosporums have simple, leathery leaves that are spirally arranged or in whorls.
Selected Pittosporum Species and Cultivars
Let’s take a look at a few selected species and cultivars of this plant that are best suited to gardening and horticulture.
- P. tenuifolium – This plant is called kohuhu, tawhiwhi, black matipo, or kohukohu. It is an upright to rounded shrub or small tree with purple to black stems and glossy green leaves with undulating margins. Honey scented maroon-purple flowers are produced towards the end of spring. This New Zealand native reaches 20ft(6m) tall and can be grown in zones 9-11.
- ‘Tom thumb’ is a dwarf variety of P. tenuifolium that reaches around 5ft (1.5m) in height. This variety produces colourful leaves that start out green but mature into a deep red color, creating an attractive contrasting effect. This shrub can be grown in zones 9-11.
- ‘Silver sheen’ is another kohuhu variety that is ideal as a screen or hedge. These plants have small, silvery-green leaves and produce maroon to brown fragrant flowers.
- P. tobira– This popular garden plant is commonly known as the Japanese mock orange. This species makes for a hardy specimen shrub with excellent salt tolerance. The Japanese mock orange grows 8-12 ft(2.4-3.7m) high and 12-18ft(3.7-5.5m) across. This plant produces orange blossom scented flowers in early spring. The flowers of this plant occur in clusters and measure 2-3inches (5-7.5cm) across.
- ‘Wheeler’s Dwarf’ – While most of the available pittosporums take on a tree or large shrub form, this variety reaches just 3-4 feet (0.9-1.2m) in height and 4-5 feet (1.2-1.5m) across. This plant has a rounded mound-shaped growth form, making it ideal as a low foundation plant or container plant.
- ‘Mojo’ is another dwarf variety, but this plant has attractive variegated foliage.
- P. eugenioides– This narrow and upright evergreen tree is commonly known as the lemonwood or tarata. This tree produces lovely honey-scented, pale yellow flowers in the mid spring. Lemonwoods have attractive glossy green leaves with white, undulating margins. A large species, this tree reaches over 30ft (9m) and should be grown in zones 9-11 in full sun.
- ‘Variegatum’ is a popular variety of the tarata that grows as a large, dense shrub. The variegated tarata has beautiful dark green and cream-white variegated foliage.
- P. ralphii is another New Zealand native that is tolerant of coastal conditions. This evergreen shrub grows to about 13ft (4.3m) tall and 9ft (3m) across. These large shrubs should be grown in a sunny spot and can tolerate quite heavy pruning.
- P. ‘garnettii’ is a hybrid of P. tenuifolium and P. ralphii. This plant reaches 10-15ft (3-4.5m) in height and grows as a dense evergreen shrub with greyish leaves with cream-white to pink edges. Greenish-purple flowers are produced in the late spring. This plant should be grown in full sun in zones 9-11.
- P. crassifolium– The karo or stiffleaf cheesewood grows to about 16ft (5m) in height and is native to New Zealand. This species has grayish-green foliage and produces deep red to purple flowers. The Karo tree is well adapted to survive strong winds and salt spray but has unfortunately been identified as a possible invader outside of its native range.
- P. dallii– grows to around 10ft (3m) as a shrub or small tree with serrated green leaves on purple stems. This species produces fragrant white flowers in late summer. This is a relatively slow-growing species that does best when grown in semi-shade.
Pittosporum Flowers
Size and flower color vary across the species but flowers all have 5 petals and become woody fruits that split open. The seeds are contained in a sticky substance, explaining the origin of the plant’s name.
Pittosporum flowers vary in color by species and can be anything from greenish, maroon, purple, or white.
Cheesewoods generally flower in the spring and early summer, depending on the species, and many have beautifully fragrant blossoms reminiscent of honey or citrus flowers that are particularly lovely in the evenings.
How To Grow Pittosporum Plants
No special preparations are needed to grow these plants from seed except perhaps to give the seeds a wash with soapy water after harvesting, as they are sticky when collected from the ripe, splitting capsules. Plant these seeds in late winter.
Pittosporums can be grown from semi-ripe cuttings taken in the early autumn. 2.5-3 inch (6.3-7.5cm) long cuttings inserted in a free draining medium that is capped with sand, is the best technique. The larger green-leaved species tend to root best. (1)
Cheesewood plants can be grown in well-drained soil. Water these young plants weekly until established and they’ll be quite drought tolerant when mature, just be careful not to overwater or grow in poorly drained substrates as they are quite susceptible to root rot.
Additionally, well-drained soil promotes moisture retention and helps maintain a healthy balance for the conservatory plants. Remember that if the soil becomes waterlogged, it can lead to adverse effects on their growth and overall health.
Most pittosporums should be grown in full sun or light shade locations, although some species such as P. dallii will do better in partial shade. Smaller varieties such as ‘Wheeler’s Dwarf’ and ‘Mojo’ make great container plants.
Pittosporums do best when grown in USDA zones 9 through 11, although some species do fine in zone 8. In colder areas, these plants will need to be grown in containers and overwintered indoors during the growing season.
Care and Maintenance
P. tenuifolium can be lightly pruned in late spring just to keep it neat and symmetrical (2). Generally, however, these plants need little pruning.
P. ralphii may need more frequent trimming to keep its growth form bushy and compact. P. tobira tends to rejuvenate more slowly than the other species after pruning. (3)
Most pittosporums will grow naturally with a single stem or leader. Prune these plants just after flowering to avoid affecting the next year’s flowering. When starting seeds, consider using a light and airy seed compost to promote healthy germination and root development.
These are pretty fast-growing plants, quite capable of growing 2ft (0.6m) a year, although their growth rate will slow as they mature. Additionally, propagating pittosporum is relatively easy through stem cuttings taken in mid summer or early fall. This allows you to create new plants and maintain your desired landscape design.
Generally, pittosporums have good resistance to pests and diseases but may be affected by mealy bugs, powdery mildew, aphids, cottony cushion scale, and sooty mold.
Cottony cushion scale is a pest that particularly affects the pittosporums and citrus plants. These sapsuckers can cause leaf drop and even mortality in plants, especially in stressful times like drought and cold. Products for scale such as Safari can be used to successfully control this pest on pittosporums.
Another unfortunate side effect of cottony cushion scale on your pittosporums is the likelihood of developing sooty mold as a result of the honeydew produced by the scale (4). Sooty mold in itself is not a serious condition but may be unsightly.
You can control sooty mold by washing it off with a strong flow of water or a mild solution of soapy water. Remember though, as long as you have scale on your pittosporums, sooty mold is probably going to be present.
Uses
Horticultural Uses
These versatile plant have many uses. P. tenuifolium can be used as a focal plant but also works great as a screen, hedge, or windbreak because of its rapid growth rate. Dwarf forms like ‘Tom Thumb’ do great as container plants, foundation plantings, and as a taller ground cover.
P. tobira, ralphii, and crassifolium are especially well suited for use in coastal areas because of their high tolerance for salt spray. Pittosporum plants can also be grown as bonsais.
Pittosporum hedge has good sound deadening properties and specimen plants can even be pruned into their basic natural shape.
Human Uses
There are records of some pittosporum species being used medicinally in both Southern Africa and New Zealand. Traditional uses of these plants include the treatment of mouth, chest, and skin ailments, as well as stomach pains and fever.
Wildlife Uses
Pittosporums are not particularly attractive to wildlife. These plants do attract bees and other insect pollinators but are not eaten by deer, which is a bonus if these animals have access to your yard.
FAQs
Why is my pittosporum turning brown?
Pittosporum turning brown can be caused by various factors, including overwatering, underwatering, poor soil drainage, fungal diseases, pest infestations, environmental stressors like extreme temperatures or drought, or transplant shock. Assessing factors such as watering practices, soil condition, sunlight exposure, and pest presence can help determine the cause and appropriate corrective actions.
Can I grow pittosporum from a cutting?
Yes, pittosporum can be grown from stem cuttings. Take a cutting from a healthy, mature portion of the plant, remove the lower leaves, and dip the cut end in rooting hormone to promote root development. Plant the cutting in a well-draining potting mix and keep it consistently moist until roots form.
Is pittosporum indoor or outdoor?
Pittosporum can be grown both indoors and outdoors, depending on the specific species and growing conditions. Many varieties are commonly used as landscape shrubs or hedges in outdoor gardens, while some dwarf or compact cultivars may be suitable for indoor cultivation as houseplants.
What’s wrong with my Pittosporum?
Identifying what’s wrong with a Pittosporum requires a closer examination of its symptoms and growing conditions. Common issues include browning leaves due to overwatering or underwatering, yellowing leaves due to nutrient deficiencies or soil pH imbalance, or wilting and dieback caused by diseases or pests. Proper diagnosis and treatment depend on identifying the specific symptoms and underlying causes.
Does Pittosporum smell?
Some species of Pittosporum, such as Pittosporum tobira (Japanese mock orange), have fragrant flowers that emit a pleasant scent. However, not all varieties of Pittosporum have a noticeable fragrance, and it may vary depending on the species and cultivar.
Conclusion
You can enjoy the beauty of these adaptable shrubs for many years if you plant them correctly, prune them every so often, and water them carefully.
For people who want to add to their pittosporum collection, stem cuts are an easy and satisfying way to do it. Let pittosporums add a touch of beauty to your scenery. If you’re looking to expand your pittosporum collection, consider visiting local garden centres where you can find a variety of these lovely plants.
They are easy to care for and look good for a long time. By following these easy pittosporum plant care tips, you can make sure that these flowers do well and add long-lasting beauty to your yard.
References
Reference list
(1) Toogood, A. Plant Propagation: The Fully Illustrated Plant-By-Plant Manual Of Practical Techniques.
(2) Brickell, C. Encyclopedia Of Plants And Flowers. American Horticultural Society.
(3) Brickell, C. & Joyce, D. Pruning & Training: What, When And How To Prune.
(4) Frank, S. & Baker, J. Cottony Cushion Scale: Entomology Insect Notes
https://content.ces.ncsu.edu/cottony-cushion-scale
Close
*image by Marinodenisenko/depositphotos
