The ‘Rising Sun Redbud’ (Cercis canadensis ‘The Rising Sun’) is an ornamental tree prized for its vibrant, color-changing foliage. Its leaves emerge in shades of apricot-orange, mature to yellow and lime-green, and often return to golden tones in autumn, creating a multi-season display. This article will guide you through the process of growing this attractive tree from seed.
Identifying and Collecting Rising Sun Redbud Seeds
Rising Sun Redbud seeds are found in flattened pods resembling snap peas. These pods develop on the tree and are ready for collection in late summer to early fall, after drying and turning brown. Select plump, healthy pods for viable seeds. Once collected, carefully peel open the pods to extract the small, kidney-shaped seeds.
Seeds can be collected from existing trees or sourced from nurseries and online retailers. When purchasing seeds, consider the source to ensure they are adapted to your local climate, as redbuds from southern regions might not tolerate colder winters. Note that ‘Rising Sun Redbud’ is a cultivar; seeds may not produce offspring identical to the parent plant.
Essential Seed Preparation for Germination
Redbud seeds possess a hard outer coating that prevents water from entering and initiating germination, and they also require a period of cold to break dormancy. A two-step preparation process involving scarification and stratification is necessary to overcome these natural barriers. These methods mimic natural processes that occur in nature, such as digestion by animals or freeze-thaw cycles, which break down the seed coat and prepare the seed for growth.
Scarification aims to break or weaken the seed’s tough outer shell. Mechanical scarification involves gently nicking the seed coat with a sharp knife or rubbing it with sandpaper for about 30 seconds to a minute. Another common technique is hot water treatment: submerge the seeds in boiling water for one minute, then turn off the heat and allow them to soak in the cooling water for 24 hours. This creates small cracks, allowing moisture to penetrate.
Following scarification, the seeds need stratification, which simulates the cold, moist conditions of winter. This process is crucial for breaking internal dormancy. After soaking, place the seeds in a moist medium such as damp sand, peat moss, or a moist paper towel. Ensure the medium is moist but not waterlogged. Enclose the seeds and medium in a sealed plastic bag or container, then store them in a refrigerator at temperatures between 33°F and 41°F (1°C to 5°C) for 60 to 90 days. This cold treatment prepares the seeds for germination in warmer temperatures.
Germinating Rising Sun Redbud Seeds
After scarification and stratification, redbud seeds are ready for planting. A well-draining seed-starting mix is ideal for germination. You can use individual pots or seed-starting trays for this stage. Plant the seeds about 1/4 to 1/2 inch deep, placing one to two seeds per cell or pot.
After planting, gently dampen the soil with a spray bottle to ensure consistent moisture. Maintain consistent soil moisture throughout germination, avoiding both drying out and waterlogging. Place the containers in a warm location, ideally between 68°F and 75°F (20°C to 24°C), with bright, indirect light. Germination typically occurs within a few weeks after the stratification period, and small sprouts will emerge.
Caring for Young Rising Sun Redbud Seedlings
Once your redbud seeds have successfully germinated, the young seedlings require attentive care. Provide them with bright, indirect light; a south-facing window or a grow light positioned a few inches above the seedlings works well. As they develop, ensure the soil remains consistently moist but not saturated, as waterlogging can lead to root rot.
When the seedlings have developed a few sets of true leaves, they can be transplanted into larger individual pots. At this stage, you may begin feeding them with a diluted liquid fertilizer, typically at half strength, to support their growth. Before transplanting outdoors, gradually acclimate the young plants to outdoor conditions over 7-10 days, a process known as hardening off. This involves progressively exposing them to increasing periods of sunlight and outdoor temperatures, preparing them for their final planting location in your garden.