Pittosporum are attractive evergreen shrubs popular in many gardens and landscapes due to their dense foliage, varied leaf colors, and often fragrant flowers. These versatile plants serve well as hedges, screens, or specimen plants, adding year-round structure and visual interest. Propagating pittosporum allows gardeners to create new plants from existing ones, providing a cost-effective way to expand their collection or share with others.
Preparing for Pittosporum Propagation
Successful propagation of pittosporum begins with careful preparation and the right timing. The best time to take cuttings is generally mid to late summer or early autumn, when the stems have matured sufficiently. For seed propagation, late winter or early spring is often ideal, allowing seeds to germinate as temperatures begin to rise. Propagating your own plants can be a rewarding endeavor, offering the opportunity to grow specific varieties and save on nursery costs.
Gathering the necessary tools beforehand simplifies the propagation process. You will need sharp, disinfected pruning shears or a knife for clean cuts, which helps prevent disease transmission. Rooting hormone, either in powder or gel form, is beneficial for encouraging root development in cuttings. Pots or seed trays, along with a suitable growing medium, are also essential. A spray bottle for misting and materials to create a humid environment, such as plastic bags or a humidity dome, will also be useful.
Propagating Pittosporum from Cuttings
Cuttings are a common and effective propagation method. Use semi-hardwood cuttings from the current season’s growth. Cuttings should be firm but flexible. Select healthy, non-flowering shoots 4 to 6 inches (10 to 15 cm) long. Taking cuttings in the early morning, when plants are turgid, can be beneficial.
Prepare cuttings by removing leaves from the lower half or two-thirds of the stem, ensuring no foliage is below the soil line. Make an angled cut just below a leaf node, where dormant cells can develop into roots. Lightly wound the base by scraping bark to expose the cambium layer, which encourages rooting. Dip the cut end into rooting hormone powder or gel, ensuring even coverage.
Plant cuttings into a well-draining rooting medium. A mix of 40% perlite, 40% coarse sand, and 20% peat provides aeration, drainage, and moisture retention. Create a hole with a pencil or finger before inserting the cutting to avoid rubbing off rooting hormone. Bury the cutting 2 to 3 inches (5 to 7.5 cm) deep, ensuring at least half is beneath the surface, then gently firm the medium around the base.
High humidity is important for successful rooting, reducing water loss as roots develop. Cover pots or trays with a clear plastic bag or humidity dome to create a mini-greenhouse effect. Use stakes or wire hoops to prevent plastic from touching leaves. Place covered cuttings in a warm location with bright, indirect light, avoiding direct sunlight to prevent overheating.
Regularly check cuttings for moisture and mold. Keep the medium consistently moist but not waterlogged. Occasional misting helps maintain humidity, especially if the covering is temporarily removed. Good air circulation prevents fungal issues; briefly open the covering daily. Rooting typically occurs within a few weeks to two months, indicated by new leaf growth or gentle resistance when lightly tugging.
Propagating Pittosporum from Seed
Seed propagation is another way to grow new plants, though slower. Collect seeds from mature plants when fruit capsules split, revealing sticky black seeds. Clean seeds thoroughly to remove sticky pulp, which can inhibit germination. Fresh seeds are recommended for better viability.
Some pittosporum species benefit from stratification, mimicking natural winter conditions to break dormancy. This involves placing seeds in a moist medium (e.g., paper towel or sand) and refrigerating for 4 to 6 weeks. Some varieties may not require this pre-treatment. Sow seeds in late winter or early spring as temperatures warm, providing optimal germination conditions.
Use a well-draining seed-starting mix, such as peat moss, perlite, and vermiculite blend, or commercial seed compost. Fill trays or small pots with the medium, then sow seeds on the surface, spacing them 1 to 2 inches apart. Gently press seeds into the soil and cover with a thin layer of medium or compost, about 1/4 to 1/2 inch deep.
Keep the seed-starting mix consistently moist but not waterlogged, using a gentle spray bottle to avoid disturbing seeds. Place trays in a warm location with bright, indirect light, ideally between 54 to 59°F (12-15°C). Germination can take two months or more, requiring patience. Plants grown from seed, especially hybrids, may not be identical to the parent.
Nurturing Your New Pittosporum Plants
Once cuttings have robust roots or seedlings have several true leaves, they are ready for transplanting. Transplant them into individual, slightly larger pots filled with general-purpose potting mix. Handle young plants carefully to minimize root disturbance. Ensure new pots have drainage holes to prevent waterlogging, which is detrimental to pittosporum.
Young pittosporum thrive with balanced light, water, and well-drained soil. They prefer full sun to partial shade; variegated varieties benefit from more sun for enhanced leaf coloration. Soil should be fertile and well-draining; while tolerant of various soil types, they do not perform well in constantly wet or poorly drained conditions. Consistent moisture is important during establishment, requiring watering once or twice a week, allowing topsoil to dry slightly between waterings.
Before moving young plants outdoors permanently, especially from a protected environment, hardening off is beneficial. This involves gradually exposing them to outdoor conditions over one to two weeks, starting with a few hours daily in a sheltered spot and progressively increasing sunlight and wind exposure. This acclimation helps them adapt to the outdoor environment and reduces transplant shock.
Begin initial feeding a few months after transplanting with a balanced, diluted fertilizer. For container plants, a slow-release granular fertilizer or liquid feed provides sustained nutrition. Monitor for common pests like aphids or scale insects, addressing them promptly with horticultural oils to maintain plant health. Good air circulation and avoiding overwatering also prevent fungal issues like root rot.