Australian Pink Hibiscus
The seeds are easy to germinate. You'll have better results if you scratch them across an emery board or sandpaper a few times, and then soak them in water for 24 hours (not more than 36 hours). Use a well-draining soil, such as 2 parts potting soil with 1 part perlite or sand. Start with small containers about 3" tall (8 cm), with 1 seed per container, about 1/2" deep (12 mm). Water the soil so that it is uniformly moist, but not soggy. For me, they sprout within 1 to 2 months when kept about 65-70 degrees (18-21°C). I've never tried spouting them at warmer temperatures. Make sure the soil surface doesn't dry out. You can keep them moist by placing the pots in a propagation dome or in a bag. Just keep it open slightly to let in fresh air.
Once they sprout, move them to filtered sun or morning sun. Water the soil whenever the top half inch of soil feels dry, but avoid keeping the soil soggy. A well-ventilated spot is best, in bright, filtered sun. Transition them to more sun gradually for the first month. Some afternoon shade might be needed in warmer areas, since this plant comes from a moderate climate. Here along the Pacific coast, it is happy in half-sun or full sun.
Long-term care: Try to keep the soil about halfway moist most of the time. Avoid letting the soil completely dry out, but don't let it stay soggy either. And of course don't let the pots sit in a tray of water.
Avoid using fertilizers that are very high in phosphorous ("bloom" fertilizers). The plant doesn't mind some phosphorous, just avoid very high levels.
Repot your plants to a larger container whenever the roots start circling around the bottom of the container or poke out of the holes. Step them up from 1 gallon (4 liters) to 5, and then finally 10 or more gallons (40 liters), depending on how large you choose to let it grow. You may prune it back to any size you wish, and this will make it bushier. Avoid heavy pruning before flowering starts in the spring. I believe the plant needs over about 40% humidity. If you grow it indoors and the air is dry in the winter, use a room humidifier to bump up the humidity.
If you have any questions, feel free to email me.
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