Growing vegetables and herbs from seed is a common practice among gardeners, but native plants demand a different approach. These plants, adapted to endure harsh environments, often require special pre-treatment for their seeds. Germination for natives also takes longer compared to other plants. To achieve optimal growth, propagate native plants during their growing season—spring through autumn. The warmth and extended daylight during these months allow the plants to develop strength and establish deep roots, making them ready for planting in revegetation sites
Choosing a good seedling
While most gardeners are confident growing vegetables, annual flowers, and herbs from seed, propagating native plants requires some special techniques. The main challenge is the fact that most Australian native plants have evolved to cope with tough conditions, including drought, frost, and bushfires. Many of them also have natural dormancy breaks, which can make the germination process much more difficult. Luckily, with the right tips and techniques, it is possible to raise healthy and resilient seedlings from native plant seeds. To propagate a healthy seedling, start by choosing a robust plant with strong foliage and roots. This ensures a sturdy root system capable of supporting the new plant once it's in the ground. After selecting a healthy plant, keep it cool and moist until planting time by placing it in a plastic bag or ice chest, away from direct sunlight. Additionally, using a potting mix formulated for native plants is advisable, as it contains low levels of phosphorus and other nutrients that new seedlings do not require. Another key step in propagating a good seedling involves taking a cutting from the parent plant. To do this, choose a healthy, well-shaped plant and cut off a branch or stem with at least three sets of leaves. It is also a good idea to remove any flower buds on the stem, as these can be prone to rotting. Once you have your cutting, wrap it in a damp paper towel and place it in an ice chest or a plastic bag. You should also try to take the cutting as early in the morning as possible to ensure that it is turgid. Choosing the best seedling for propagation is essential because some plants have very poor germination rates, while others have infertile or damaged seeds. To improve your chances of success, collect the seed from a healthy, natural population and avoid isolated or cloned plants, as they cannot cross-pollinate and may produce unhealthy offspring.
Taking a cutting
Many native plants can be successfully propagated from cuttings, providing a simple and effective method for expanding your garden collection. By taking cuttings from healthy, thriving plants, you can create exact replicas of your favorite specimens, preserving their unique characteristics and contributing to biodiversity conservation. When selecting a plant for propagation, focus on healthy individuals that are actively growing. Avoid taking cuttings from plants that are currently flowering or budding, as these may not root as successfully. Once you have your chosen plant, prepare it for propagation by removing the bottom 50 to 75% of its foliage. It's also a good idea to dip the cut in rooting hormone, and Nancy suggests covering the first node with it (if your plant has no nodes, then leave it uncovered). The optimum time of year for propagation is spring to late summer. This provides warmth for germination and long sunny days for seedling growth in tubes. The warmer months are also a good time to harden off the seedlings before planting them in your garden. To ensure successful propagation, it’s essential to use the right soil. Cindy and John recommend a seed-raising mix to give your cutting the best chance of developing roots. The soil should be disease-free and well-draining. If the cutting loses too much water, it will wilt and die. Some seeds require special pre-treatment to encourage germination. This includes seeds from native plants in the Fabaceae family, such as Lilly pillies and hardenbergias. These plants have a tough, impermeable outer coat that blocks moisture. Smoke treatment helps crack this coating, allowing the embryo inside to be moistened and hydrated. The heat from the smoke also increases the germination rate. Other seeds need a cold winter to trigger germination. This is particularly important for plants from alpine regions, such as snow gums. You can stimulate germination in these plants by fermenting the fruits. This will cause the outer layer to decompose, allowing the inner seeds to be harvested and stored in the fridge.
Taking a seedling from a plant
Propagating native plants often begins with the crucial skill of taking cuttings from seedlings. While many gardeners feel confident growing vegetables and annual flowers from seed, propagating native species requires specialized techniques and greater patience. Numerous common Australian plants are better suited to propagation via cuttings rather than seeds. Taking a cutting from a parent plant will produce an identical clone, but the rooting and maturation process can take anywhere from a few weeks to over a year. Though it may require more time and care, mastering the art of cutting propagation is a valuable technique for gardeners seeking to cultivate native flora. Unlike growing from seed, this method ensures the new plants will share the exact genetic traits of the original specimen. It is important to select a healthy plant from which to take a cutting. A healthy, disease-free plant will be more likely to survive and thrive once it is planted. You may also want to consider using a rooting hormone, which is available at most garden centres and can help your cutting to grow roots faster. You will also need to make sure that the soil is suitable for your cutting. It should be free-draining and low in nutrients, to mimic the conditions in which native plants grow. It is a good idea to use a specialist native plant mix, although standard potting soil can be used as well. Most native plants are drought tolerant and have evolved to cope with the aridity of much of Australia. They also respond to complex dormancy release cues, such as heat, nitrate and smoke, and will delay germination until the conditions are ideal. This makes them more difficult to propagate than exotics, which often germinate with ease. Maori seeds are very small, so it is important to open the seed packet carefully. This will prevent the seeds from blowing away in low winds. It is a good idea to open the seed packet in a greenhouse or other warm, shaded area to prevent the seed from dying. The easiest way to plant is to spread the seed on a layer of sand. The seed then sticks to the soil, and a fine sand layer allows water to penetrate. Sand also helps retain soil moisture to prevent it from drying out.
Taking a seedling from a seed packet
While a lot of gardeners are comfortable starting vegetables, flowers, and herbs from seed, native plants might be more difficult. Since many of these plants have adapted to survive in adverse environments—such as droughts and bushfires—their seeds might need extra care to sprout. This entails spreading out germination over an extended period and postponing germination until the perfect conditions are met. The fact that natives have a sophisticated system for dormant release cues and are acclimated to drastically varied settings could be two of the possible causes of this. In addition to providing a list of the seeds, a seed packet will usually contain information about the plant’s growing requirements. This may include information about how much sunlight the plant prefers, and whether it requires a particular type of soil. It will also indicate the best planting time for that species. For example, some natives are sown in spring, while others are sown in summer and bloom the following year. In addition, the packet will tell you how long it takes for a seedling to mature. To increase the likelihood of successful propagation, it is advisable to apply some pretreatment to the seeds. Pour boiling water over the seeds and soak them. This will reduce the brittleness of the seeds and promote germination. It is important to keep the medium moist at all times, as some of the original seeds are particularly susceptible to rotting. Using appropriate containers is also important. For wildflowers, standard seed trays or punnets are suitable, while for trees and shrubs, forestry tubes are appropriate. It is also recommended to use a specialized seedling mix that is well-drained and low in nutrients to more closely mimic the environment in which the seeds and cuttings will grow. After the seedlings begin to form roots, they can be transferred to a larger pot or container. It is a good idea to continue feeding the seedlings with a liquid or powder rooting hormone, as this will help them to develop strong roots. However, it is important to avoid too much fertiliser, as native plants are prone to be overwhelmed by the concentrated minerals in typical feeds. A low-phosphate feed is best, and a light top-dressing of slow-release fertiliser is advisable.